/fill comand displays wrong amount of blocks in its output when filling with air and "destroy" fill mode

Steps to reproduce:

1. Run /fill ~ ~ ~ ~-2 ~-2 ~-2 air destroy while standing on a surface

Observed result:
The command's output will always say that there were 0 blocks filled regardless of the actual amount. It doesn't happen when the fill mode is "replace" instead of "destroy".

Expected result:
The command's output correctly states the amount of filled blocks.