Spigot 1.12.2
Tried DEV BUILD 403 and Lastest version
No /reload only restart

Error: ( https://gyazo.com/1ced385be26f0e985fd38c4386d2a96c )
Or just 'Disabling Protocolib' And i don't know the problem
Someone may help ?

I finnally find the source, it's a plugin in my case it's MineWebBridge, wich allow link between CMS and Minecraft, It cause this error, after disabling it, it worked fine

This issue is the same like #518