I'm having this issue and I made absolutely sure that I didn't have any tm gain.
Datadisks: 2x stacking offense, 1x heal over time, 1x vitality, 1x leader's resolve, 1x savior
Team: slkr, hux, st, fost, kru
Whole team loses health and becomes quite frail. I still am doing well farming a lot of droids as I can keep slkr in ult until the last minute and a half. But still curious why my team is losing health...am I missing something here?
Edit: was going to mention also losing protection, which OP had mentioned as well but I just noticed that is the modifier reflecting damage back.