/fill does not always send block updates

Maybe partwise caused by MC-5898

Demonstration of bug using command blocks: https://gfycat.com/PessimisticWealthyJackal

Added to the description, thanks!

in 1.12-pre1

Seems to occur with fill commands if the fill location coordinate places blocks to the positive X or Z of the target command block(s).

Set up a fill command on the ground and place a /say command 2 blocks higher. Now use the following example in the fill command block.

Example:

This works:
/fill ~-1 ~3 ~ ~3 ~ ~ redstone_block

This doesn't work:
/fill ~1 ~3 ~ ~3 ~ ~ redstone_block