I have a 1000 pages (or so) PDF with annotations in dttg4. While reading, scrolling and making some annotations it is likely to jump to an entirely different section/page. Sometimes scrolling from page x to x+1 it simply jumps back to page x or x-1. Other times it jumps to an entirely different section a few hundred pages elsewhere. Seems entirely random when it happens. I am careful not to tap any embedded link.
By far most of the annotations were made in dttg3 at which time i noticed none of this jumping around.
Before I could test with auto-sync off, I took my iPad on the road (i.e. no wifi) during which none of the jumping was present. Now back on wifi (and auto-sync still on), the problem no longer presents itself (of course). Something got sorted out I guess - that syncing may have been the issue.
Well the jumping is back even with sync turned off. I can reliably have dttg “jump” in the pdf if i switch to another app (ie dttg goes to background), and immediately return back to it. In the big pdf it will shift over tens of pages. Then in a much smaller 25page doc without annotations it does the same but jumps over perhaps just a few pages (back and forth btw, not just one direction).
when i first reported this dttg jumped pages while i was viewing the doc, this is a little different backgrounding dttg but perhaps similar enough for you to get a handle on it.
Also, returning to dttg after a long time (say a day or more), always shows me “nothing selected” even though i had a pdf/document open at the time i switched away to another app. Again, just mention this as it may be a related issue.