I am having the exact same problem on my KeyLab Essential 49.never happened until I updated Pigments this morning.
updated MidiControl Center and KeyLab's firmware. problem remains. the Next button stays lit no matter what. after a computer restart it's off, stays off when using any othe VsTi but as soon as you launch any Arturia instrument it comes on and stays lit. also, the back button does not light up anymore at all.
since I didn't have the problem previous to updating Pigments I'd say it's not normal and actually quite annoying.
any help from Arturia would be highly appreciated...