Hello YAG, here are a few more results.
The problem occurs when the machine or the application sets idle for at least 5 minutes. The problem only occurs for checkboxes that are added to a tabpage. Other checkboxes that I use in my application that are placed directly on a form work fine.

The problem can be reproduced with the virus protection disabled.

The problem is not project specific, I added a checkbox to a tabpage on another VB.NET app (no code for the checkbox) and the problem was reproduced.

I also have a delay in accessing the menu after the app sets idle.

I hope this helps.