Ouch - unfortunate (and unhealthy) environment.
Pretty standard fare though. There's tension between them. Something is dangling unprocessed.
Only two likely outcomes.......
It either comes out and gets processed or it continues to fester until something explodes.
Not easy to be the middle person in such a dynamic but if you are brave enough you might want to call a 3 way "sit-down, let's talk and see if it can surface and get processed" meeting. As an offer of help to THEM - not from your own discomfort. If it's perceived as "all about you" things won't likely come out.
Good luck !