Varunda

i also had this issue. it was caused by including the api in the shaded jar. by adding an exclusion i was able to get it to work fine

i've found another fix based on: https://www.spigotmc.org/threads/unable-to-modify-entity-metadata-packet-using-protocollib-1-19-3.582442/ implemented it in my fork: https://github.com/Varunda/XGlow only tested with 1.20, but it seems a bit simpler to implement for me than #30