"Is moving on ground" returns true while player is standing still

This is either a bug or a misleadingly named node since it only returns false if I’m jumping or falling.

It’s really just saying “you are in walking movement mode”. I added a new alias “IsWalking” that is going to come in 4.3 that means the same thing, if that helps. If you care whether you are actually moving, you can check the Velocity.