Keyboard shortcuts not working on new assignments?

Have noticed this frequency across Mac and PC, but on the fly I will be updating key commands (see other threads about not porting over key bindings from previous versions), and sometimes the functions will not work on new assignment?

These are commands that are free of system settings or other function in the app , and the same ones I have used in previous versions, yet is seems like an application relaunch, or even a system relaunch is needed for these to take effect? Yet even then, sometimes they may or may not work after such, and sometimes days from reassignment will just randomly work (or not). Just wondering why this would be?

Recent example is I just reassigned Channels> Select Above and Below; the stock settings work fine. When I change them, only one seems to work (above), then changing back to stock, neither work until application relaunch, then trying to reassign the opposite pairing works correctly (below), and does not fix on application restart.

I will try with a full system reboot, but that seems unreasonable when needing to update hot keys (and often is not the fix). This is standalone BTW

Thanks!