I could be missing something extremely obvious, but it seems like I can't scroll items TO the cursor, but only away from it. This is only an issue in the inventory screen however, going between containers seems to have no issue whatsoever.
For example, if I have half a stack of arrows in my hotbar and half a stack in my bulk inventory, I can't hover over the hotbar and scroll the inventory items into them, I can only scroll them out. Its not like this is game breaking, so can almost certainly be low priority, since the items can just be shift clicked or whatever.

EDIT: I noticed it on the 1.19.1 version

I think the hotbar is treated as the same inventory in many cases (since it is technically the same inventory) and that's why some of the move actions won't work between the hotbar and the main inventory.

I'll look into this during the planned rewrite of the mod.