Hey Andre, this was a bug which was fixed in the 2025.2 release:

Great! Is there also a fix available? 

Yyou can reallow editing by changing the Layout procedure of the process_step table. This Alter statement works for the 2025.1 SF version:

alter procedure [dbo].[lay_process_step]
(
   @layout_mode tinyint, -- 0 = add, 1 = update, 2 = navigate
   @import_mode tinyint, -- 0 = regular, 1 = import row, 2 = export, 3 = import

   @add_button_type    tinyint output, -- 0 = enabled, 1 = disabled, 2 = hidden.
   @update_button_type tinyint output,
   @delete_button_type tinyint output,

   @model_id                       "model_id",
   @branch_id                      "branch_id",
   @process_flow_id                "process_flow_id",
   @process_step_id                "process_step_id",
   @last_process_action_id         "process_action_id",
   @last_process_action_successful "process_action_successful",
   @order_no                       "order_no",
   @abs_order_no                   "abs_order_no",
   @next_process_action_id         "process_action_id",
   @process_order_input            "no_yes",
   @process_order_output           "no_yes",
   @alias_process_step_id          "alias_process_step_id",
   @process_step_description       "process_step_description",
   @insert_user                    "tsf_user",
   @insert_date_time               "date_time",
   @update_user                    "tsf_user",
   @update_date_time               "date_time",
   @generated_by_control_proc_id   "control_proc_id",

   @model_id_type                       tinyint output, -- 0 = editable, 1 = read only, 2 = hidden inside form, 3 = hidden outside form.
   @branch_id_type                      tinyint output,
   @process_flow_id_type                tinyint output,
   @process_step_id_type                tinyint output,
   @last_process_action_id_type         tinyint output,
   @last_process_action_successful_type tinyint output,
   @order_no_type                       tinyint output,
   @abs_order_no_type                   tinyint output,
   @next_process_action_id_type         tinyint output,
   @process_order_input_type            tinyint output,
   @process_order_output_type           tinyint output,
   @alias_process_step_id_type          tinyint output,
   @process_step_description_type       tinyint output,
   @insert_user_type                    tinyint output,
   @insert_date_time_type               tinyint output,
   @update_user_type                    tinyint output,
   @update_date_time_type               tinyint output,
   @generated_by_control_proc_id_type   tinyint output,

   @model_id_mand                       tinyint output, -- 0 = optional, 1 = mandatory.
   @branch_id_mand                      tinyint output,
   @process_flow_id_mand                tinyint output,
   @process_step_id_mand                tinyint output,
   @last_process_action_id_mand         tinyint output,
   @last_process_action_successful_mand tinyint output,
   @order_no_mand                       tinyint output,
   @abs_order_no_mand                   tinyint output,
   @next_process_action_id_mand         tinyint output,
   @process_order_input_mand            tinyint output,
   @process_order_output_mand           tinyint output,
   @alias_process_step_id_mand          tinyint output,
   @process_step_description_mand       tinyint output,
   @insert_user_mand                    tinyint output,
   @insert_date_time_mand               tinyint output,
   @update_user_mand                    tinyint output,
   @update_date_time_mand               tinyint output,
   @generated_by_control_proc_id_mand   tinyint output
)

as
begin

  -- Do not count affected rows for performance
  SET NOCOUNT ON;

    --control_proc_id:      layout_hide_alias
    --template_id:          layout_hide_alias
    --prog_object_item_id:  hide_alias_process_step_alias_process_step_id
    --template_description: Hide alias fields when the RDBMS type is SQL Server

    -- Hide alias fields when the RDBMS type is SQL Server
    if exists (select 1
               from model
               where model_id = @model_id
                 and rdbms_type = 0) -- SQL Server
    and @alias_process_step_id is null
    begin
        set @alias_process_step_id_type = 3
    end

    --control_proc_id:      layout_process_step_always
    --template_id:          layout_process_step_always
    --prog_object_item_id:  layout_process_step_always
    --template_description: Ensure a process step last-success cannot be modifed when the previous process action was a start or decision node

    -- The success type may not be changed for steps following start- and decision nodes
    if exists (
        select 1
        from process_action p
        where p.model_id = @model_id
          and p.branch_id = @branch_id
          and p.process_flow_id = @process_flow_id
          and p.process_action_id = @last_process_action_id
          and p.process_action_type in (98, 100))
    begin
        set @last_process_action_successful_type = 1
    end

    --control_proc_id:      layout_generated_read_only
    --template_id:          layout_generated_by_control_proc_id_read_only_parent
    --prog_object_item_id:  layout_generated_by_control_proc_id_read_only_parent
    --template_description: Generated records will become read-only

    if @generated_by_control_proc_id is not null
    begin
        set @update_button_type = 1
        set @delete_button_type = 1
    end

    --control_proc_id:      layout_generated_read_only
    --template_id:          layout_generated_read_only_child
    --prog_object_item_id:  layout_generated_read_only_child_ref_process_flow_process_step
    --template_description: Children of generated records will become read-only

    if exists(select 1
              from process_flow
              -- Check if the parent is generated
              where (generated = 1 
                    or generated_by_control_proc_id is not null 
                    )
               and model_id = @model_id
               and branch_id = @branch_id
               and process_flow_id = @process_flow_id
       )
    begin
        set @update_button_type = 1
        set @delete_button_type = 1
        set @add_button_type = 1
    end

end
go

​@Mark Jongeling  I need the layout of the task (lay_modify_process_step). 

Good point, here is the one for the modify task:

alter procedure [dbo].[lay_modify_process_step]
(
   @layout_mode tinyint, -- 0 = add, 1 = update, 2 = navigate
   @import_mode tinyint, -- 0 = regular, 1 = import row, 2 = export, 3 = import

   @confirm_button_type tinyint output, -- 0 = enabled, 1 = disabled, 2 = hidden.
   @cancel_button_type  tinyint output,

   @model_id                       "model_id",
   @branch_id                      "branch_id",
   @process_flow_id                "process_flow_id",
   @process_step_id                "process_step_id",
   @process_step_description       "process_step_description",
   @last_process_action_id         "process_action_id",
   @next_process_action_id         "process_action_id",
   @last_process_action_successful "process_action_successful",
   @order_no                       "order_no",
   @abs_order_no                   "abs_order_no",

   @model_id_type                       tinyint output, -- 0 = editable, 1 = read only, 2 = hidden inside form, 3 = hidden outside form.
   @branch_id_type                      tinyint output,
   @process_flow_id_type                tinyint output,
   @process_step_id_type                tinyint output,
   @process_step_description_type       tinyint output,
   @last_process_action_id_type         tinyint output,
   @next_process_action_id_type         tinyint output,
   @last_process_action_successful_type tinyint output,
   @order_no_type                       tinyint output,
   @abs_order_no_type                   tinyint output,

   @model_id_mand                       tinyint output, -- 0 = optional, 1 = mandatory.
   @branch_id_mand                      tinyint output,
   @process_flow_id_mand                tinyint output,
   @process_step_id_mand                tinyint output,
   @process_step_description_mand       tinyint output,
   @last_process_action_id_mand         tinyint output,
   @next_process_action_id_mand         tinyint output,
   @last_process_action_successful_mand tinyint output,
   @order_no_mand                       tinyint output,
   @abs_order_no_mand                   tinyint output
)

as
begin

  -- Do not count affected rows for performance
  SET NOCOUNT ON;

    --control_proc_id:      layout_process_step_always
    --template_id:          layout_process_step_always
    --prog_object_item_id:  layout_process_step_always
    --template_description: Ensure a process step last-success cannot be modifed when the previous process action was a start or decision node

    -- The success type may not be changed for steps following start- and decision nodes
    if exists (
        select 1
        from process_action p
        where p.model_id = @model_id
          and p.branch_id = @branch_id
          and p.process_flow_id = @process_flow_id
          and p.process_action_id = @last_process_action_id
          and p.process_action_type in (98, 100))
    begin
        set @last_process_action_successful_type = 1
    end

end
GO

Thanks!