How do I clear my action bars?

Ok, there is technically a way to do it but it's next level jank.

Fill you action bar with an ability that you have because of passive point investment. Respec your passives such that you don't have that ability unlocked any more. It will automatically remove it from your action bar.

I don't know off the top of my head. If I was going to start investigating it, I bet that the ability assignment request has a null check in it somewhere that fails if you try and set the ability to nothing. It actually asks the server if it's ok to assign that skill. We try to reduce network calls wherever we can do it's probably checking the null value before it even asks and just isn't bothering because it thinks it's a pointless request. Even though it's not.

Basically someone probably forgot about it.