Comments disappear sometimes

hi, when I log in to my google drive and double click to open the PDF file, it shows me some comments. but then when i open the documents with Kami, some comments disappeared. i changed browsers and changed computers. It doesn’t help. The problem still exists. Would you please help? I share the file with my students so that i should be able to see all the comments.

Also, I am able to reply some comments. There are other comments that i can’t reply. Please help.

Do you mean comments or annotations? I haven’t used comments yet, but I found today that as I was writing my annotations sometimes disappeared. I accidently discovered that zooming made the annotations reappear. No idea why, but it worked on 3 different documents. Might be worth a try.