1.8 player can't do something on 1.16 servers

[Elikill58]

Describe the bug, provide any errors No console error.

After login, 1.8 can run commands, talk etc but can't move or place block

How can we reproduce it? Steps to reproduce the behavior:

1. Login with 1.8.9 client
2. Move
3. See you be teleporter back

Expected behaviour Can play.

ViaVersion Dump: ViaVersion dump

Additional server info The plugin "EliTest" only include one event that send message, nothing else.

Checklist (mark with [X] to check)

• [x] I have included a ViaVersion dump
• [x] If applicable, I have included a paste (not a screenshot) of the error
• [x] I have tried a build from https://ci.viaversion.com/ and the issue still persists
• [x] I have looked at https://www.spigotmc.org/resources/viarewind-legacy-support.52924/ and it does not offer a fix for my problem

IMPORTANT: Follow the Checklist or we can't reproduce your issue and your issue will be closed

[Barvalg]

[Elikill58]

Oups. I didn't tried with dev build of ViaVersion/ViaBackwards.

That's the same. My Via dump: https://dump.viaversion.com/c6487f72b92b3bc6decc64cafe8d2d41b0689f6c3869aa2995f1c3c3c8d0da61

[Barvalg]