1)
when you crash trying to practice a grade, that's it the mission is gone, you log back in and you must now wait 20 hours to practice that grade - this needs fixing
2)
if you crash when you aleady accepted the mission and handed in the 4/4 occupation items to practice, then you get back in, practice (give the answers as needed) you get nothing (there is a fix, in this case you abandon the mission but you lost your 4/4 items BUT you still get the chance to practice again right away not have to wait 20 hours
when you crash trying to practice a grade, that's it the mission is gone, you log back in and you must now wait 20 hours to practice that grade - this needs fixing
2)
if you crash when you aleady accepted the mission and handed in the 4/4 occupation items to practice, then you get back in, practice (give the answers as needed) you get nothing (there is a fix, in this case you abandon the mission but you lost your 4/4 items BUT you still get the chance to practice again right away not have to wait 20 hours