position not syncing when falling

Expected behavior

client position and server position should be the same while flying

Observed/Actual behavior

player position is not sync with the server position while flying and syncs when touching the ground

Steps/models to reproduce

1. connect with 2 players,
2. one of them stands somewhere, the 2nd player flies far away at high speed and then back to the player.
3. then compare the position between the two players. (the position should be different)

Note: (the player should still fly, because when he touches the ground, the player position is synchronized).

Plugin and Datapack List

plotsquared, fastasyncworldedit

Paper version

This server is running Paper version git-Paper-54 (MC: 1.20.1) (Implementing API version 1.20.1-R0.1-SNAPSHOT) (Git: 8582999)
You are running the latest version
Previous version: git-Purpur-2004 (MC: 1.20.1)

Other

https://www.youtube.com/watch?v=RjGqo-xQTLA

Use the reported two-player reproduction on Paper 1.20.1: have one player fly away at high speed and return while remaining airborne, then compare both players' positions. Trace the server-side flying position synchronization behavior; done means the client and server positions remain synchronized before the player touches the ground.