Dealing with mutual friends

Here's my brief story.  Recently lost my best friend as they ended the friendship.  There was a lot of misunderstanding and hurt feelings we were both to blame but they took the major offense.  I've tried reconciling but they aren't having any of it.  It's been nearly a year of not speaking.  I've learned to move on and past it, but admittedly some days are harder than others.  We have a mutual friend, lives across country but recently came to visit.  We had to plan separate events, which was odd but we made it through.  However, the mutual friend and I haven't spoken since.  Mainly occasional likes and comments on Facebook posts.  She knows details of the friend split, that I'm sure I don't even know, but lately has been changing her profile pics to photos of the two of them and writing things about how wonderful the ex-friend is.  I'm not against their friendship (they were friends first) but can't help feel she's doing a bit of this on purpose.  It's bordering on obsessive (I think) but it's also starting to annoy me.  I have said and done nothing about this and will continue to do so but thoughts welcome.  It almost feels as though she is asserting herself as if to say - haha we're still friends and you're not!

I should also point out - we are all in our 40s so certainly old enough to know better!!!