I had four creatures in play, but only two are relevant to explain this bug. I had Bulwark Ox and Caradora, Heart of Alacria out on the board in a standard best of one match. Caradora had two +1/+1 counters on it. My opponent played stasis snare, targeting Caradora. In response, I sacrificed Bulwark Ox to give all my creatures with counters Indestructible and Hexproof. Despite the sacrifice trigger resolving, Caradora was still exiled under the Stasis Snare. My opponent controlled no effect that would have negated Hexproof such as Nowhere To Run so, from my understanding of the rules, the temporary Hexproof given to Caradora should have protected her. Sadly, I took no pictures.