Markups randomly deleting when marking up pdfs in the files app?

for class I have been downloading the pdfs from my class notes to make edits of mi own to the notes.

I save the PDFs onto the files app on my iPad and occasionally it will randomly delete all my markups.

I searched online and apparently this has been a problem for over 4 years. Why has apple not addressed this. Many people mentioned the entire markup deleting even after their work was saved. Some suffered greatly from working for hours only to be disappointed and have to start completely over.

This is now November of 2023, Apple… please fix this already. There is no point in having this feature on the iPad if it is unreliable, it is currently a waste of space and time until it is fixed. I will now have to switch to a competitors software because of this bug that has not been fixed after over 4 years, if it has gone this long unfixed there is no telling if it ever will be.