Lightroom sometimes looses the ability to use command+L to turn filters on / off

Hello,

I use command+L a lot to switch quickly between filter on and filter off (especially when deleting photos).

Again, after some time it happened, that it stopped working to turn filters on. No matter which filter I use (preset or manually), command+L only works one more time to turn filters off. Second command+L does NOT work to turn filters on again. Every following command+L shows “Library Filters Off”.

When this happened before, AI told me (after trying many changes in settings and restoring files) to restore an old Lightroom catalogue. This worked then, and I did so because I did not loose many changes and hoped, the error would never occur again. 

But today, the idea of going back to an old catalogue causes sweat and tears.

Why is the ability to switch between filters on/off stored in the catalogue?

The above described solution can not be the only one! How can I get to turn on and off filters (with command+L or by using the menue) to work again as intended? It is too time consuming and destroying a fast workflow if I have to remake the filter or reopen it from the presets. 

Thank you 

Best regards 

Rainer