Was the low cadence prescribed (Unlikely for TR I think) your choice, or just how you felt on the day?
I tend to drop the cadence when I get tired, I'm not able to keep the cardio working, so move the load to the muscles - I understand it is not ideal, but my thinking is that I can also do this out on the road, and it's a form of strength training.
Re your power dropouts - what turbo is it, and by what means are you connecting?
I used to get occasional drop outs on Ant+, but since moving to bluetooth (Moved to virtual shifting so had no choice), and a mega cheap USB 5.3 dongle (On the end of an equally cheap 2m extension cable), it's been bullet proof.