OMG I had the same problem. It was originally placed Monday nights but was then moved to Thursday mornings, which then conflicted with my math. I went to the office place and asked, and they said to use Solar to fix it. All I did was go to Solar and opened up the master timetable thing and searched up Engineer 1EE0 and looked at the times of when its available and compared with my own timetable. Then in solar I modified the saved 1EE0 to the same core as the one that fits according to the master timetable. In mycase I switched from C04 (thursday morning) back to C01 (monday night, how i originally had it).
hope this helps!