normally, doing chat battle is just for fun. Rank is unchanged no matter who wins.
recently, I tried to have a battle. I, however, realized I brought wrong mech, so I quit the battle in order to change. And I lost one of my stars
what is that? intentional thing by devs (so people should suffer in chat battles would they encounter wrong opponent) or a bug (which wasn't in game until recently)
UPD weird, I now have old amount of stars. But, I looked after doing 2 more battles, one I won, in other my opponent quit