What is your Set Visibility(to return to visible) tied to?
If you connect it to the Movement controls - you need the check to be sure they are actually trying to move. (Axis Value != 0)
If that is not working, you can just make a timer to check for actual motion, regardless of input (it also makes you appear if ‘bumped’ by an opponent, etc)
Set a Timer and create a corresponding Custom Event.
Have that check to see if you are "hidden’ and if so - Get Velocity.
get Vector Length from that to see how ‘fast’ you are moving (by any means) and become visible if there is significant movement.