combat Creatures can parry attacks from behind

I saw this happen a few minutes ago while I wasn't recording, so I turned on OBS and tried to replicate it. Took about ten minutes to reproduce it, but sure enough, the leper gnomes can parry attacks from behind while they're running away. I'm guessing this applies to other NPCs that flee as well. I've attached a video, it happens about 37 seconds in; I've also attached a screenshot of the exact moment it happens.

Obviously, the way parry is supposed to work, NPCs (and PCs) are not supposed to be able to parry attacks from behind (block should work this way as well, I didn't test for that). This was an explicit change made in patch 1.3.0 and this has been the intended behavior ever since, even with parry becoming more or less irrelevant in the most recent expansions.

This is on the MaNGOS WotLK test server (Covenant, Solar Flare). Observed and reported 10/26/2018.