Thanks for writing that up! Was there anything to be learned from those 13 sporadics or are they simply truly sporadic?

Thank you!

Yeah, one lesson is that if you relax your halting condition to entering a loop at some point you get much longer runtime, see machine Skelet#1 (https://bbchallenge.org/1LC1LE_---1LD_1RD0LD_1LA1RE_0LB0RC), enters a loop after 10^51 steps and the loop is 10^9 steps long.