Named Selections disappearing on mac

Several times now today I have saved a set of polysurfaces and after doing a few other things in the file, the named selections window is empty of my previous selections. I am not changing any of the objects that were in the selections. Tried re-opening the file etc, still gone.
Anyone else experiencing this?
I’ve had to go back to the SelKey workflow I was using in V6.
Rhino 7 on Big Sur.

Can you post a file and the steps for the other things you do before losing the named selections? I haven’t seen this.