Today I was questing with Bastion in Glenumbra, doing the quest Ripple Effect. Since questing with both companions since I unlocked them on June 2, I get the green popups saying rapport increased for some things, but it remains in the same yellow-green position just right of the center of the progress bar. Their responses to asking about friendship remain the same. But, didn't think much of it until during a fight with a ghost, one of the mages of the camp started attacking and I killed it on accident. I received a 1200 gold bounty and to be attacked on sight by guards. Bastion's rapport did not decrease or increase. It remains at the exact same point it has been in the yellow-green just slightly right of center, and his responses to my asking about friendship is still the same as it was.
I would assume a murder would cause a large decrease to his rapport. But 0 decrees, makes me think maybe there's a bug happening. I decided to test it, so I took Bastion into the Duke's house in Aldcroft and stole an item. The popup said rapport decreased, but when I check the progress bar, it is in the exact same spot. Either the amount the amount for murder and stealing is tiny or something is wrong.