Session Termination issues

We've just acquired floating licenses and found that web users need to explicitly log out of in order to release floating licenses. This is the documented behavior and works properly.

However, when a user ends their session by closing the browser tab, the floating licenses are not released. My concern is that other session resources are not released as well.

I suspect we may be having this issue because we are using a custom user management repository. What do we need to do to ensure that a user's resources are cleaned up when a session is ended by closing a browser tab or the browser itself?