I am having issues getting locomotives to face opposite directions on double headed trains. Both locos face the same direction and when I rotate the loco it disconnects from the train and I when I reconnect the problem resurfaces.
Oh my, you have found a bug! I get the same results in 0.17.71. There must have been a change in Factorio that messes with my directional logic and/or replacement sequencing. Do you know what version this surfaced in? I'll take a look at the code when I get a chance.