Console spam when someone on 1.8 joins into 1.20.4 backend server

[Rubenicos]

/viaversion dump Output

https://dump.viaversion.com/8a500372d3825c7d7689bc241936de5fdc279f06dcfc4ff0b0d0eb0e42f90b15

Console Error

https://mclo.gs/JtalD4H

Bug Description

When someone using 1.8 joins into 1.20.4 backend server the console start spamming

Steps to Reproduce

1. Login with a 1.8.8 client on 1.20.4 server

Expected Behavior

The console spam should not appear

Additional Server Info

No response

Checklist

• [X] Via plugins are only running on EITHER the backend servers (e.g. Paper) OR the proxy (e.g. Velocity), not on both.
• [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 the latest build(s) 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

[Barvalg]

[FlorianMichael]

It looks like some plugin is sending invalid data, try if it also appears just with Via* plugins installed, if that's not the case, try to perform a binary search on your plugin list:

1. Remove half of the existing plugins and put them aside for now,
2. Run the server again,
3. Is it still creating errors from there?

(If yes; Repeat from step 1 with current items) (If not; Swap out the current plugins with the ones set aside and repeat from step 1)

4. Repeat process until problematic plugin/s are found.

[Rubenicos]

The problem is caused by TAB plugin