I have just had one of my users report a problem sorting lists when using groups. I have fixed this by making the following edit to 1.0.9
In file blocks/attendance/updateAttendance.php around line 97 I changed
$students = get_group_users($currentgroup);
$students = get_group_users($currentgroup, "u.$sort ASC");
This has resolved the problem for us and does not seem to have caused any problems so far.