Often when I try to scroll to the top of the metadata pane the text jerks down again, making it nigh impossible to get to the top.
I can't reproduce this, assuming I understand what you mean, on my iPad 3. And if there is any device that is going to have a weird bug like that, it'd probably be an iPad 3. So... Not sure. I'd try deleting and re-adding the app to your device. I've had this fix issues with JRemote in the past (and plenty of other apps).
Sometimes when I turn my iPad from landscape to portrait view, the GUI gets messed up with parts ending up in the wrong places.
Unfortunately, rotation in UIKit is all broken in iOS8. The 8.3 update improved things (my iPhone 6 used to get stuck all the time in landscape and refuse to rotate until you force-quit apps), but the "keyboard/panel/partially rotated" bug is still there. Here are just a few lovely examples (in Apple apps):
https://twitter.com/ronkorving/status/543752566698287104http://stackoverflow.com/questions/26928528/ios-8-orientation-issues-keyboard-ends-up-in-incorrect-positionSo, not saying there isn't something they can do, but this problem is pretty widespread and applies even to Apple's first-party apps.
Sometimes the Now playing view shows an old Now playing list and the wrong album art for the currently playing track, while the bottom pane, at the same time, shows the correct information including the correct album art. This problem can be solved be reloading the Now playing list from within JRemote, but I think the playlist should be updated automatically, since the current behaviour doesn't serve any useful purpose.
I still see this occasionally, though it seems to be way better than with older versions for me now. Updating the album artwork does lag behind the file starting playback, but it usually fixes itself now.
But, not always. Usually once it gets "out of sync" if you do next/prev track once or twice, it fixes itself.