I haven’t been able to find a solution online for this.
Using the FPS controller asset bundled with Unity, I found that double tapping spacebar causes the player to jump and then jump again automatically upon landing.
(BTW, This also happens with a 3rd person character prefab I purchased on the Unity store.)
I can’t see why this bug would be preset in a universal asset such as FPS-Controller, so I feel like it’s my fault! Is there something I can do to fix this?