If a Character has JumpMaxHoldTime set to something more than 0, on client it can jump even in mid-air as many times as the player wants, even if JumpMaxCount is 1. The server does not correct the movement of the client, so the client can practically fly everywhere (possible network exploit?).
The problem does not occur if the Character is controlled by the server.
- create project from third person blueprint template
- in ThirdPersonCharacter set JumpMaxHoldTime to 0.5
- in the Play in Editor dropdown set Number of Players to 2
- start pie
- in client viewport press space repeatedly, the character will go up with no limits