I found, that with my new phone several apps had an other behavior than on other phone with Kitkat. That is:
You have a list like in Fdroid a list with apps. Scroll a little up and look for more information of one app. You read that info and want to go back to the list by back-button. Where to you land? On my FP2 I get to the top of the list and not to the list and the scroll-location where I have been before. This last outcome I was used to.
And that is just like that in 2 more apps. The worst back-behaviour I get in New-Pipe version 0.7.8: I search, get a list, pick a video and play it. When the video ends, I get back to that one item, the next back-tapp should get me back to the list, but Newpipe exits. Newpipe version 0.7.6 takes me back to the list, so the difference of both versions could be a key to some special knowledge. Do you see he same behaviour on yourFP2?
Spielmops