Bug: Train convoy will not cease 'mirror schedule' operation

[merry]

On a number of occasions, I have experienced a condition where a train convoy (or line) is first built with a 'mirror' schedule, because there is only one platform at each station on a fairly simple single line with the occasional passing  loop outside stations.
Later, I add extra platforms, and modify the schedule or line to operate without mirror.
However, sometimes the train continues to run through the schedule in reverse. None of the 'mirror', 'alternate direction', or any other visible option are set, but it continues to operate in this way. It does not matter whether I modify a line or individual schedule, the reverse operatoin of the schedule continues. I have tried assigning the convoy to another line, and then reverting it to the original, I have sent it back to depot and removed the schedule, i have created an individual schedule, but it continues to operate in mirrored schedule sequence.

What i have found is that to reproduce, the convoy must be running in mirrored schedule at the time the schedule mirror is removed.
The only way to stop the mirrored operation is to return it to depot, sell the convoy and buy a new one. Not at all convenient!
Unfortunately, I do not ahve any savegames with this condition in place (I just get really frustrated and now 'solve' the issue by replacing the convoy manually before saving!).

One for further investigation

[Vladki]

There is a checkbox on the convoy info window, just uncheck it.