List of Glitches that happened
KingNero Fever : caused people to only see air around them when they joined and then they disconnect
Corpse Mod Issues : 1.12.2 had issues where people couldn't access their corpses, 1.16.5 had issues where the NBT tags were too long due to astral sorcery/demon slayers so Gluon couldn't read death histories
When CelestialRealm II launched, people couldn't do anything because the claim protect wouldn't let them
When CelestialColdWar launched, people couldn't craft modded items due to a bug with Mods v Plugins
World Divided has a issue where Dark's space suit turned into books due to unimaginable lag
At one point on CelestialRealm I the custom recipes stopped working so Dark was able to craft items that were removed like the OP ice dragonsteel sword that froze people and did 20+ damage
CelestialRealm I had a issue where people could get past the world border and survive, people could also clip out of the minigames thus taking the minigame stuff back to the overworld
CelestialRealm I Tinkers Pockets had a duping glitch which Royal abused to get infinite money, Gluon stopped him before he could transfer the money