McLib - 2.2.2
Metamorph - 1.2.6
forge: 2854
pixelmon: Pixelmon-1.12.2-8.1.2-universal

Issue: server gives console error when a player is morphed as a pixelmon. A delay of about 1-30 seconds. Then they get kicked with internal server error. I believe the issue has something to do with sound.

Console output when player is kicked: https://pastebin.com/cMjcFHAU

Does walking while morphed as such result in the game crashing sooner?

yes