If I remember correctly, this happened in Everquest Frontiers. You’d catch some shitty AoE debuff in town and give it to other people, including attackable NPCs like guards. Guards were not easy to kill, so they just carried that shit for weeks. The only way to remove the debuff was die, but it just kept spreading, so the best way was to not coach to other towns, but Freeport was basically fucked. That was SOE for ya, and they did that shit on purpose.