Catalyst arena infinite streak formula seems to have changed once again.
Using the new formula for maintaining an infinite streak in the catalyst clash arena (2x3,30 4*/1,25 5* plus a 4,40 4*/2,35 5*, 10000 team PI minimum) seems to net you a death match now. Would advise to now only use 1 x 3,30 4*/1,25 5*. The other 2 champs must be rated higher or risk being deathmatched.
I'm gonna assume this holds true in the 4 and 5 star featured arena as well.