Had an Issue with PDF

I had a bug where once I downloaded my whole notebook as a pdf, and send it to my Mac, like the writing would disappear after looking at it once?? Not sure if it make sense but it would disappear after looking at it once and all that would be left is my paper. I had written out a whole assignment so I had to do a work around of sending it to Goodnotes to get them all in a png all at once then go through a png to pdf converter and that seemed to work I think it’s just the pen tool and pdf not really working together?

Just wanted to know if others had the same problem or if it’s just me.

Thanks for reporting it - can you give me some details about this PDF, how many pages, what type of content was inside (just writing, or lots of images, etc), and what file size was the actual PDF file?