Nexus Clash

My good Ele sits in the SH with pets set to Aggressive to Non-Allied most of the time

If a hostile neutral/good character participates in a raid, my pets will attack them and I will not lose MO (as designed)

However, it appears that after I am killed and my pets stick around due to Tenacious Summoning, their continued attacks now start dropping my MO. Is this intended? They are still defending the SH, even if I'm no longer there.

Definitely a bug, and not intended. It may be pretty annoying to resolve, though - the stronghold morality-override code checks "are we in our stronghold?" by asking whether the character shifting morality is in their stronghold. Since you're dead, you're not.

Another possible scenario would be if a Lich plops down Bone Guardians in their stronghold and goes somewhere else.

Yeah, I can imagine a few scenarios where pets are at home and the character isn't. Or, the reverse and pets are left somewhere to cause trouble, but the character safely sits in the SH and immune to the MO impact of the pets.