This only occurs since the last update.
i have noticed after a while of sculpting the app will get stuck in a mode where i try to sculpt and see the geo deform under, however when i release it snaps back “close” to the initial starting point.
so if i draw a stroke that pushes it down 4mm, when i release it will return to a deformation of maybe 1-2mm… so does affect it and does deform it, however doesnt do the actual stroke.
i get this also with all tools. The move tool, rotate, everything will snap back.
Generally noticed this after 1-2hours of sculting and my ipad is hot like a potato. generally i close the app, wait and come back and it will be fine. tough to repro, but next time im sculpting ill try to catch a video of it.