With some of the font changes and changes in one/many usage order on the menu, there are also changes in the sizes of objects in your inventory, sort of reverting to a big-hugeness when being moved which they briefly had a while back. When you try to move items (into or out of bags or into SDBs), they expand into a bigger stack (if more than 1 item in slot), which makes them larger than the item you're trying to move them into (bag, slot, or SDB). And the center of the "moving stack" is slightly off-center, so you THINK you've got the stack positioned over the bag you want it to go into, but really it's one off, and it goes into the wrong one.
There wasn't really anything broken about the previous image of a thing when you were moving it, so it probably wasn't necessary to fix it? Anyway, looks like a bug to me (in terms of things being moved into the bag you didn't mean to put them into), so here's a notice about it.