Minecraft 1.16.5
Forge 36.2.2
Wings 2.0.1

I've noticed whenever a player dies or connects this gets spammed twice in the console log with increasing Netty Epoll Server IO numbers.
[Netty Epoll Server IO #15/ERROR] [net.minecraft.command.arguments.ArgumentTypes/]: Could not serialize me.paulf.wings.server.command.WingsArgument@2c69a61 (class me.paulf.wings.server.command.WingsArgument) - will not be sent to client!
[Netty Epoll Server IO #15/ERROR] [net.minecraft.command.arguments.ArgumentTypes/]: Could not serialize me.paulf.wings.server.command.WingsArgument@5cca381e (class me.paulf.wings.server.command.WingsArgument) - will not be sent to client!

I am also having this issue; if I have more mods in my modpack players cannot even connect to a server due to oversized packet errors, and it wasn't until recently I was able to go through my logs and find that right before the server crashes, it's this same 'could not serialize' error twice, and then
[Netty Epoll Server IO #3/ERROR] [net.minecraft.network.NettyCompressionEncoder/]: Attempted to send packet over maximum protocol size: 2361740 > 2097152
only to spam my console with strings of numbers until the entire server completely shuts down.

I really love this mod, please look into this, I don't want to have to remove it from my modpack but as they said above, this is literally game-breaking.
I would like to attatch my 'latest' log but it literally won't allow it due to the size of the file, caused by the data spam that happened just before the crash.

Same issue here. It is game-breaking