From time to time I accidentally create a reference or other object in model space which belongs in lyout space. Occasionally I correct this by copying the objects from model space and scaling them way down in layout space. I think this causes instability and eventually Rhino will crash.
I’m using Visualarq so it may also be related to it.
I notice that as I look back in my backup files after a crash that several sections which were active in a number of viewports are no longer active. And I know that I did not deactivate them.