Comments Disappearing [Android]

When I leave comments in adobe acrobat on my Galaxy Tab S6 Lite, the comments sometimes (like 60% of the time. It increases with the more I write in one go) disappears after I unselect the 'Add drawing' button. The comments still show in the comment list where, when selected, appear again and I can see the opacity is 100% but again disappear when not selected. 

I tried reinstalling the app to get the same problem occuring