lookup combo on web accepts non-listed values

Hi all,

I have something weird in my web gui. In the lookup fields, I check in the table 'location’ with a combo

This will show suggestions; 

When I enter a invalid value, i get prompted and can't save the record.
 

However, on web, I can save the record; 
 

BUT, when i check the record, it is not saved in the Db;

When I refresh, it's still there. When I change between tabs, still there. 

In Subjects specified; 

When I close the table, and open it, it's gone (as it should be). 

GUI; 2021.2.12.


Is this a bug, did something change? What's going on?