I don't think this is the error he is referring to. I've seen several complaints in the last few days of AI buses following incorrect paths. I'm not sure why all of a sudden this is an issue.Its to do with Left Path. OMSI doesn't support it thats why buses drive on the pavement. Unfortunately there is no way of fixing it unless OMSI bring out a patch for it.
Which AI list were you using? I believe that this is a problem as already mentioned with TTData as I'm fairly sure I had that same issue when I was running B9TL's on the map. Problem is OMSI does not support RHD and so it can cause bugs.It's started to happen to me with the introduction of the C400 so is it a problem with the revised `AI list?