Interesting!
A bit late, but if it ever happens again, I have a vague memory of this being caused by having two instances of EAC active at the same time. Maybe you have/had a game that kept its anticheat or EAC open at all times by accident (it either failed to close or keeps starting on its own). So ye, if it happens again, might be worth taking a peek in task manager and seeing if something like that is happening.