Bumping Lesson Plans Causing strange behavior

I loved the idea of being able to shift lesson plans forward and backward. But for some reason, even after getting rid of all special days, bumping lesson plans still has unexpected results.

I will have open slots for lesson plans that forcibly remain open slots, and simply shift with the rest of the lesson plans. What I’d expect is the lessons plans to shift in to those open slots. A potential reason might be because the slot had previously been used by a lesson plan that got removed, or it was a day marked as a special day.
I can’t quite figure it out. Anyone else have this issue?

Hmm, this is odd, I haven’t heard of any issues with bumping lessons. Could you share some screenshots and some specific steps to reproduce, it’s been very busy around here but I will try and take some time to check this out before the v23 string freeze.