Interesting, I'm having similar problems.
Annoying thing is I discovered what it was after buying a new Note 4 :S was about time to upgrade from my Note 1 though but the battery drain was one of things that prompted the upgrade.
Interesting, I'm having similar problems.



haha!
So 5.1 stock ROM is worthwhile you say?
I'm sure MM will be along by April.

largely they just seem to change the UI around for the sake of it, sure there are some underlying changes but a lot of fairly basic usability issues are still unresolved or less than ideal from Android 2.3 :S i.e. editing and manipulation of multi-line text, granular and better configuration control over notifications and so on and some of the better, but a little bit buggy features have been stripped out and replaced with less useful but still buggy features 
haha!
So 5.1 stock ROM is worthwhile you say?
I'm sure MM will be along by April.

MM is a nice step up in responsiveness and smoothness.
Is that reason enough?
tend to keep mine fairly tuned.

Does it not go away when you select always?
I have seen people previously mention this as just "one of those bugs". As you say, drives me insane. It does it all the time! Links for browsers and videos opened in Root Explorer/ES File Explorer are the worst offenders.
still, can't complain at that.