All of this has been happening to my rogue as well - Can’t generate combo points until I kill the target, in which they all appear but I can’t use them in combat; Mounts won’t summon properly but instead make it look like my character is running faster and it won’t dismount for regular dismounting actions; exclamation mark doesn’t go away when accepting a quest.
The mount bug is liveable with, but the combo point bug makes combat a bore because I can’t use a lot of my abilities. Disabling addons didn’t help, reloading didn’t help. Pls find a solution for this bug, it is quite annoying and completely throws all combat rotation out of the window