Action bar targeting circle vanishes when switching targets
When changing targets to different party members the action bar will become bugged in such a fashion that hitting enter while targeted on a party member will not bring up your action bars target circle and you wont be able to move along the bar. All you will be able to do is cycle party members and hitting enter will not put you on the action bar. To reset it you must completely detarget and then retarget again, as a healer who switches targets often this is particularly annoying because I will switch targets only to have to detarget and retarget to get use of my action bar again.
Edit : Source of this seems to be moving the camera with the mouse by holding right click. Every time I moved the camera this way the action bar would glitch like this.