So this one is rather weird.
Say I am copying the value from Cell A into Cells B & C:
Cell A (my Copied cell) doesn't have any border formatting.
Cell B has a border that I drew by dragging out the border area with the pencil tool.
Cell C has a border that I manually clicked on each side to create.
When I paste from A to B, I lose my borders. When I paste from A to C, I keep them. If I manually draw over borders I'd already have, the new borders aren't erased when their cell is pasted over.
It's almost like there's a difference in the borders I draw over an area than the ones I draw manually.
What's going on here?