VFP 26.2 doesn't work when connecting to a 1.21.4 server

[Alluseri]

General Information

ViaVersion Dump URL: https://dump.viaversion.com/c5a0a53b61b3cba892166187f8c6e1c4ff21d5fd850eead5dd5190304ef828be
latest.log URL: https://mclo.gs/PnsQ6Mp

Bug Description

Connecting to a 26.2 server that uses ViaBackwards down to 1.21.4, with the Minecraft version 26.2, with VFP version set to 1.21.4, causes this error.

Steps to Reproduce

1. Open Minecraft 26.2 with VFP
2. Set VFP protocol version to 1.21.4
3. Connect to a 26.2 server with 1.21.4 ViaBackwards (e.g. 9b9t.org)
4. Get the linked error

Expected Behavior

There should be no network protocol error.

[Barvalg]