I was playing my wizard in a PFS game earlier this evening and ran into the following interaction. I summoned a Hound Archon at a rather nasty Erinyes (SR 19), and had the celestial puppy go over and whack it. At this point, the GM informed me that I needed to make an SR check against the Erinyes, and if I did not make the SR check, the Hound would instantly disappear back to whence it came.
I can't find evidence of this in the rules for SR or summoned creatures, or in a search of this forum. The ruling was justified by making an analogy to the cleric spell Spiritual Weapon, though I have issue with that due to Spiritual Weapon having SR: Yes and Summon Monster IV having SR: No.
Anyone aware of a ruling, FAQ, or chapter I'm missing that says summon monsters have to make a CL check against SR or be unsummoned?
Thanks in advance!