Unbeatable squads?

I keep running into a lineup of Teebo, RG, SunFac, Fives, and Aayla. They're all maxed out level 80 7*, but I will run out my own level 80 7* lineups and I cannot defeat this squad. It's not even close. I spent my 3 highest rated squads at it in a row in the GW (all maxed out) and I managed to kill only the RG and got fives really low on health. I spent the entire rest of my team trying to kill the remaining characters and left a full health Sunfac and Aayla standing. Is this some kind of glitch that these characters are totally unbeatable together?