The mixin likely needs to be moved to the CommandTreeS2CPacket.ArgumentNode.write method. Additional logging would be beneficial here for mods that do not register their argument types to the class map because of silent breakage introduced by the argument type refactor (mods should register using ArgumentTypeRegistry instead).
Note that argument types now sync using raw IDs as well, and Velocity seems to represent crossstitch:mod_argument as the raw ID -255.
The mixin likely needs to be moved to the
CommandTreeS2CPacket.ArgumentNode.writemethod. Additional logging would be beneficial here for mods that do not register their argument types to the class map because of silent breakage introduced by the argument type refactor (mods should register usingArgumentTypeRegistryinstead).Note that argument types now sync using raw IDs as well, and Velocity seems to represent
crossstitch:mod_argumentas the raw ID-255.