booky
Quilt mappings are somwhat different to fabric, as they use hased mojang mappings as intermediary mappings. I don't know if yarn mappings are even possible on quilt loader and quilt...
The log filters which are used don't work when using quilt. I don't really know why, but the `LogUtils#getLogger()` method (which is used everywhere in vanilla) doesn't call log filters....
Quilt mappings were very easy to integrate (181974a8ebda29846858a828309bf9598dc4af36), they provide intermediary (fabric) -> quilt mappings on their maven. The incompatibility with quilt still exists, so this issue can remain open....
same issue as #764 but with the actual cause mentioned
which client version? do you have any pluigns on your velocity proxy? which velocity version have you installed?
I can't seem to reproduce this  Did you change anything in plugin/server configs or do you have other plugins installed on the backend server (which use protocollib/packetevents)?
Does this happen when joining the velocity proxy or when switching between backend servers?
The stacktrace doesn't match with your code. You call `ProtocolManager#getUser` in your provided code, but the stacktrace errors at `PlayerManager#getUser`
Please try the latest jenkins build and test if the problem persists
which packetevents version are you using?