Server authoritative movement: Creative mode flight sometimes desyncronizes when switching quickly in singleplayer

Ever since 1.21.60, switching to Flight Mode multiple times in quick succession in Creative Mode occasionally causes the server and client to desync. The server forces the player to the ground repeatedly despite the client attempting to allow the player to fly up. This issue occurs on offline, singleplayer worlds. It is not a connectivity issue.

Steps to Reproduce

1. Enter a world in Creative Mode.

2. While near the ground, switch to flight mode, then back to normal mode, then to flight mode again, and keep flying upward (hold space).

3. Repeat until you observe the player being “teleported/forced” downward despite being in flight mode.

Expected Results

Entering flight mode in Creative Mode allows you to fly.

Observed Results

The server authoritative movement changes from 1.21.60 sometimes prevent flight mode from working in Creative.