I've been having this weird problem/bug since patch 1.18 is out:
Usually, I play mainly using my keyboard. So I press 1-0 to make my character use the skills I put in the slots.
Most of the time the skill I want to use is used.
But sometimes, my character just uses some totally different skill, for example when I press "3", it uses the skill I put on "8"!
That's a serious problem, because that may cancel out selfbuffs or start some skill with a reaaaally long casting time when I actually tried to heal someone close to death.
Sometimes skills I put into the action bar slots just vanish in the middle of a fight and the skill I had put into the slot previously shows up again.

Sadly, I can't say WHEN exactly it happens, because it happens randomly.
Anyone else experienced this problem?