Command blocks kick player when entering certain commands > 256 characters in multiplayer

The bug

While entering certain commands in a command block on a multiplayer server the client is kicked:

Internal Exception: io.netty.handler.codec.DecoderException: The received string length is longer than maximum allowed (265 > 256)

Apparently not every string causes this, for example 32500 * "a", or /say with a similar large text works fine.

How to reproduce

1. Enter the following command

   execute if entity @e[type=!minecraft:player,name=Apprentice,tag=!Apprentice] as @e[type=!minecraft:player,name=Apprentice,tag=!Apprentice] at @s run advancement grant @p[distance=..10] only elkia:starwars/sithapprenticeaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa

2. Place the cursor right behind the last character ("e") type a character, for example another "a"