Did Mycomancer today and Tank Brann was essentially useless outside of curio procs. He did ~200k DPS on the boss and ~30k DPS on the ‘Particularly Bad Guys’. Not sure if maybe there’s something weird with the Magni transformation, but it felt really wrong.
I hopped into the Sinkhole delve afterwards and the Brann Tank damage was as expected which was ~5-20x higher than in Mycomancer depending on the type of pull.