Disappearing handwriting in iPad Notes app

Taking handwritten notes in the native Notes app on my 2021 iPad pro, I frequently encounter the following problem:

I am writing, and after I lift the apple Pencil from the page, about half of the letters in the word I just finished writing disappear completely. eg. I would handwrite the word 'frustrating' and a moment after I start the next word there is a sudden disappearance and all that is left is 'fr st ti g'.

When this starts to happen it, happens with almost every word I try to write in the note. Needless to say, taking any sort of comprehensible notes becomes nearly impossible.

I've also noticed that when this happens, the iPad starts to get very hot to the touch. I wonder if this has something to do with the ML handwriting analysis/'straightening' trying to do too much and failing. I've repeatedly searched for a way to turn this feature off, but with no success.

I've tried exiting the Notes app, turning the iPad off for a while to allow it to cool down, then returning to the note. Unfortunately, this does not fix the issue. The note appears to be permanently broken and I have to start in a brand new file.