I believe I found my issue, the Tuba engine heats up the other engines around it very easily, even though visibly the plume is not touching the other engines. Not sure if this is a bug or intended, but it "feels" like the engines shouldn't be heating eachother up. And I don't think that the heat is sinking into the rest of the ship and then going all the way to the other engines, there is a lot of mass to heat up if it was transfering that way.
Also, notice that at the first burn in the video at ~74% throttle, nothing explodes, and then at ~15% percent throttle with the craft in a different orbital orientation the engines heat up and explode quickly. The other craft I was trying to dock with was about 5km away if that matters.