Thank you, I gave it a shot and ran around in circles like a psycho casting Holy Shock and Light of Dawn, and unfortunately it still randomly stops movement whether pressing buttons or not. I can be holding down both the left and right mouse buttons and running, and it will randomly come to a full stop with them still pressed. I tested out the default middle mouse button to steer earlier when I reset everything, but it really messed with my normal rotation/movement, middle mouse button is usually either Fel Rush or consecration. Any more ideas?
Darkxgoddess,
Hm, okay, if it’s not the SpellActivationOverlay function, what if we try to drop the entirety of Timertracker? If this doesn’t work, it’s likely not one of our elements, but some other third party application or something like that.
/run TimerTracker:Hide()
Sorry for the late reply, this seems to temporarily fix it. Still no noticeable event or action that triggers the issue but hopefully the extra steps helps people out 
Appreciate you following up on this Darkxgoddess. We’ll stick with this as a work around for now. I’d also recommend submitting this as a bug report using the in game tool next time you see it so our QA folks can check it out. The in game tool collects some info on your UI elements which may help them find out why it’s erroring for some but not everybody.
I will say, I was having this issue just after 9.0.1 was released, and I was able to fix the issue by disabling AtlasLoot. I know a lot of people here did say that they aren’t using this Addon, but I’m adding this response here because it’s the top search result when looking up my issue, and it may help some people that are using this addon.
Edited by Blizzard - this topic is being locked as the issue was resolved for the original poster. Please create your own thread or contact support.