Granting the ability "Mayfly" to players without op, in survival has some strange effects. Attempting to fly when a user has the ability in survival mode causes the player to fly for 1 tick, then immediately stop flying. Holding the spacebar/jump button causes the user to rapidly start flying and stop flying. Players with op can still fly normally with the ability regardless of gamemode.

Steps to reproduce:

1. Have a player in survival mode, without op get Mayfly using the command "/ability <User> mayfly true"
2. Attempt to fly as the player with that ability
   Observed result:
   When the spacebar/jump button is pressed twice to fly, the player enters flying, then immediately stops flying. When the jump button is held afterward (ON MOBILE ONLY), the player with the ability will start and stop flying rapidly (This result may vary based on the server refresh rate or latency). On PC, nothing happens after holding the spacebar after double tapping the spacebar to fly.
   Expected result:
   The player without op, in survival, and with the ability should start flying as if they were in creative mode, whilst still being in survival. Holding the spacebar after this should cause the player to rise upwards smoothly.

This issue was not present in previous versions. Players without op in survival mode could fly as if they were in creative mode, whilst still being in survival. None of these issues affect the owner of the world, even if they don't have op themselves. Please fix this because this was very useful for mapmaking.