When generating a timetable from a usual file, I found that the file for years/students (**** _ years_days _ ***. Html) shows question marks where versions before (until 2016) it showed the division of the class with different teachers. The HTML file for teachers looks okay. The problem appears for classes with the restriction "A set of activities has same starting time (day + hour)".
I'm not sure if it's a bug or if I'm commenting a mistake. It occurs that before (in files for real situation) the problem did not occur. When testing in older versions of the FET (same computer), the problem repeats itself, whereas before it did not occur. Attached a simplified file. If you don't mind, see "teste2017_teachers_days_horizontal.html" generated: I see "???" where before I saw the classes to "S2a" and "S2b" (a divided student set as groups).