Vines lost when shearing many at once in a single block space

The Bug

See the screenshot for an example. It took four vines to place – one for each block face. When using shears, only one vine is returned. You can lose vines by simply filling a block space with them, then using shears and repeating.

Expected behavior: one vine dropped per side covered
Actual behavior: exactly one vine dropped

How to reproduce

1. Place two blocks down, one block apart from each other
2. Place a block behind the gap and above it, see screenshot
3. Inside the hole, place a vine on each exposed side
4. In survival mode, attack the vines using shears
   notice that the vines block drops only one vine, despite having 4 within its block space