I experienced the same problems that you mentioned.
I run LOS 14.1 on a Nexus 9 tablet.
Downgrading/reinstalling to 2.8.2 “solved” the problem temporary.
In the version 2.9.3 I also noticed, that if I zoom in, the map got white.
Have you checked with the official osmand release from google play (or in the issue there is a direct apk download linked as well.) if it experiences the same behaviour?
I don’t have play, but I just tried the apk offered on their web page. It seems to work as expected.
I will test F-Droid’s newest version again later (can I upload screenshots/videos here?).
Regardless of that, I wonder if there is a fully free software alternative for OsmAnd+. As stated in the anti-features, the license for the layouts and artwork is proprietary (CC-SA-NC-ND). Also, I often find that the UI is quite bloated.
I’ve updated to 3.0 version on F-droid and it is a little improved but scrolling / rendering times are still about 3-5 seconds compared to 8 in the previous version