Signs disconnects players on Fabric 1.21.5 Server

[Gui0Cri]

Minecraft version: 1.21.5
FabricAPI version: 0.16.14
Fastback version: 0.24.0 fabric
--FabricAPI and Fastback are the only mods installed--
On a fabric hosted server, when loading a chunk with any sign placed all players have their connection lost and the following error:

Internal Exception: io.netty.handler.codec.EncoderException: java.lang.NoSuchMethodError: 'net.minecraft.class_2487 net.minecraft.class_2487.method_10562(java.lang.String)'

Only way to fix it was removing fastback or loading the save on a singleplayer world to break the sign.

latest.log

[Schm1m]

i got the same error, versions are the same, but fabric api version is 0.121.0 for me, 0.16.14 ist the fabric loader version