Lies!
proof or it didn't happen!
No, really, I really doubt about it, they're not even friends anymore...
As far as I know, those are just rumors shared by many people, from different sources.
My best guess, by doing a minimum IG research is that they f*cked when Cowboy and Miesha went together to Pittsburg. Same event, promoted by their mutual manager (Kevin Harvick), most probably same hotel (logistically by their management, it would be easier to put them on the same hotel); and Caraway in London doing something for Affliction Clothing. Everything points at them being alone and together.
Then this video:
(timestamped)
I've heard many people around internet telling this about them. Dunno if fighters in general knows or talks about this, or if it's a well known rumor. (I've heard about Cat Zingano and Cowboy story too, so maybe Cowboy has lots of stories to tell or rumors to spread)
The most important part here is: If you were cowboy, what would you do? the answer is obvious.