To bump lessons, a cell must have at least one incomplete lesson.
Bumping is performed according to the schedule of the lesson, which visible on the schedule tab when updating. The schedule is set by the repetition schedule when a lesson series is created, or defaults to the course default schedule.
When bumping, scholaric targets the next available date, or previous available date, of the lesson depending on the bump action (earlier or later). The date will naturally skip holidays and vacation days, but not event days. Note that when bumping a cell with multiple incomplete lessons, they could have different schedules, resulting in different target dates.
The date of the lesson is updated and then the process is repeated within the target date, if the target date has incomplete lessons, and only for those incomplete lessons that have the same schedule as the original lesson. In this way, Scholaric won't continue the bump chain, for example, a MWF lesson scheduled on Wednesday, when the previous lesson was a MTWTF lesson, scheduled on Tuesday.