Game mode: Online, Official, Any
Problem: Misc
Region: All
While you can setup defences to easily farm bosses, bosses are also used in an attempt to wipe any purge defence people have. The issue is that bosses can be pulled an unlimited distance from their spawn.
I suggest bosses gets linked to their spawn location. So they teleport and instant heals after a certain pull distance.
Steps on how to reproduce issue:
Aggro boss.
Pull it to someone else base with thralls standing out in any way.
See it wipe it all. Repeat if defence can kill it.