Some keybindings stick, others seem to disappear. No problems when entering or exiting combat.
Using nUI 5.06.10 (Plus)
The first screenshot show that the keybindings work, but the ones from the second screenshot don't seem to stick. The keys are ALL saved in the keybinding interface, but they don't show on the actionbars and pressing the keys don't perform the action. It's pretty safe to say that if it doesn't get shown on the actionbar, it doesn't get set.
Very weird.
Just thought I'd add some more weirdness to an already weird problem.