Much like me Entangling Roots someone in the path of the horse-back Light’s Hope guards and watching them get murdered…
Also faction-guards don’t act like the low-level city guards do and chase down any hostile NPC nearby.
The intended behavior of neutral town guards is to ruthlessly kill anyone engaged in PvP, with varying degrees of hostility based on reputation with said guards. In this particular case, a unique NPC is spawned (the Infernal) that is PvP-flagged (because Vanilla-era Warlock flavor) that causes anyone damaged by its initial summoning to take PvP-combat damage (thus flagging them) but crediting that damage only to a mere NPC (who go unnoticed by these kinds of guards).
If we make town guards nuke NPCs, you solve only the problem of penalizing the Warlock partially, as it may still fail to flag them after the fact.
If we make the Infernal changed, outside of altering the PvP flag portion, I’m not sure an easy hotfix is available since so much of it is Vanilla-like.
The guards are acting exactly as they’re supposed to, virulently hostile on a hair-trigger to any PvP-combat regardless of how it starts or is participated in. Reputation with said guards has some seeming Vanilla-flavor balance on this as well, but I couldn’t give a crap to dig further on this. The possibly easiest fix is the Infernal itself, but given the wonky order-of-operations and Vanilla-intent of summoning such an entity around “civil” folks, I’m not sure that’s actually true.
This is as Vanilla-like as MC-ing Mattingly to reset Ony and a host of other weird, probably unintended, but otherwise true to Vanilla quirks. I couldn’t care less about something that is incredibly niche and avoidable and find the angst over it pretty funny, notably when the OP is a multi-boxer who regularly ruins someone’s day.