I visited the frost giants today and had some weird happenings. After killing the frost king I noticed it was like someone was blocking my character every time I walked. So I cast Witch sight. It turns out multiple invisible imposters “Osric Vales” were actually following me closely (The player wasn’t actually online)! I suspect it’s some spell-related thing. An invisible Frost king was also following me. I can’t really say when or how it started happening, but I definitely noticed it after killing the king.
I noticed that Greater Bestow has been changed, I don't know if it could be related to that?
Admiral Captain Mathilde Wintertal Thigh Highs, Run a Rig merchant! Bringer of Fire, Bane of Hair, Summoner of Bones, Table Dancer of the Broken Goblet!
Maealyn Cloudcreek, Priest of the Hearthkeeper
Emma, Monk Karen Smith, Techsmith of Gond
It is likely related to Programmed Image/Misty Vision, yes. With more people using it these days (thanks to Misty Vision), it's probably more obvious, but I expect this bug has been around for awhile.
I can look into it, but I didn't write the code for this and it's a bit hard to understand.
Tarina — The Witch of Darkhold, a dealer in spirits and black magic
These invisible dopplethingies have been around for a while now, since as far back as one of Rasaels updates... I think it was the one with the big changes to the bigbys line and the implementation of feats like lunge, but any ability like rangers exacting strike and arrow abilities will create a clone. Even spells like the planar binding line will spawn them, although you will only know those are there because you can hear the clones spell effects and will find a patch of walkmesh that gets blocked. The hostile/targetable version used to be found all over the place after that update, but are very rare now.
Sadly, such things are created when you use any summon spell. It's a part of summoning code (i'm not sure why they are needed, but i guess, it's needed in first place). Not sure if it's possible to get rid of them without remaking whole summoning system.