Auto-refresh is done based on the last refresh timestamp generated by the client, as the client and server can be out of sync for many reasons this leads so situations where the auto-refresh works incorrectly.
This can lead to extra or missing refreshes.
My suggestion is to include current server timestamp in the reply of the entity or auto-refresh procedure and use this as the input parameter to send with the next auto-refresh check.
This way we are never in situation where we can have any desync of clocks.
I am aware there are ways to avoid this issue but all are a workaround to essentially a solvable issue.