How to re-validate a selected user from a group?

Question

PHP

Hello. Please tell me what could be the problem. The code should be used to check the user for belonging to a certain group. It works correctly, but the re-selection of the "Chairman" / "Chairman", the check does not occur. Those. I need to forbid all the group, except for certain ones - to choose "coffee break" and "drinking water". If I select a user at the very beginning, then the script works, but if I reselect the user, then the user's check for belonging to a group does not occur again. Unfortunately, I am not a developer or even a junior, so I have a problem understanding this bug. I am attaching the source code.

Answer 1

The error was not in the cache, it was in the incorrect return of values ​​​​after the department was determined. Transformed the return from 3 to 1, started to work out. After I corrected the display of checkboxes when checking.

Answer 2

It looks like fortune telling.
Even in the provided source, there is no changeLinkedMeetings function, which most likely switches values, but without reloading the page.
Most likely, this is the reason. When the page is loaded, a check is made, and when the user switches, the page is not reloaded and, accordingly, access is not rechecked.