Disappearing PDF markups glitch

I think this might be a glitch in the iPad but I find that on occasion when I am taking notes via the markup feature on the PDFs I have saved in my device whether They are saved to the iCloud folder or my personal one, that I have lost certain markups and it saves incompletely. This is frustrating because I end up losing a lot of notes that I type into a sticky note or a lot of my highlights but not some others which makes going back very confusing...

My iPad us up to date and I have reached out to technical support about this issue before. They were unable to help me. They only offer solution or assistance for using the iBooks app or some other viewer but not the general PDF viewer in iPad that allows you to make markups. I also was connected to the internet the whole time and allowed the changes to be uploaded to the iCloud before I opened the file again. I find the issue happens right after saving and I want to open the document up again minutes later, the markups are gone.

I believe the issue is similar to https://discussions.apple.com/thread/252083280 but I don’t know what the outcome was for this person but my experience with technical support was not helpful.