Tried SLKR vs SLKR and both team members were impossible to beat forever. See the attached image. Note that the defending team had new DC level 15 for Night vision Rey. Other counters did not work ...
Ideas
I'm gonna need to see your .gg report on that. JMK prevents TM manipulation, so she can't reduce your TM for your loop. GK and Snips are slow, so that is why it took so long for you to be able to damage their team. You just need to understand the teams you're using.
Infinite loop is with the mirror. JMK just does not have any chances and destroyed in seconds. Ok. Good luck to beat the SLKR with this DC when everyone would have it. And let's wait for the round stats. I'm pretty sure that the win rate by any team would be very low or even 0.