Extruding exact number issue

I am in countering an error when I try to extrude. When I begin, I am unable to select the number and put in an exact value, for example 2mm. If I close the project and open it again, it will work for a little bit and stop again. I’m working on an iPad Pro with an Apple Pencil. Is this a known issue? Am I doing something? Help!

https://support.shapr3d.com/hc/en-us/requests/new