I work with two machines MBPro and MBAir, have a Lightroom catalogue on my NAS drive and so my files are always in sync (I work only with one machin at a time). Works fine for all the pics but now I have the problem that the collections, and only the collections, are not longer synced, all the pics work well, but not the collections. Has anyone a hint for me how to fix this?
I'm surprised by your claim that you have your catalog on the NAS. Lightroom Classic cannot work with its catalog on a network volume, and would normally refuse to save the catalog in that location. You can store your pictures on a NAS, but normally not the catalog.