SubD Undos

I’m editing vertices on a SubD surface, and when I undo, I can only go back 3 or 4 steps. Is that normal?

thanks

no that is not normal,

can you run _SystemInfo in Rhino and post back the results?
Does this happen with any model, say a simple SubD box or sphere?

If it is model specific, can you share the model?

it happned only in my surface… only 3 Undos…

well: