Armorer Bug in HD Remake

Bug is still there in HD Remake.

I've run following tests. I've created this map in editor:

Blue town has Castle, red heroes (A and B) are both lvl 1 Clerics with 0 Defense and have army of 100 Goblins (2 Defense creatures, for some reason Peasants are not available in my editor). Hero A has Armorer Expert. I run multiple sieges and took notes of damage done by top tower (it deals more damage than side towers) - I've put down 50 attacks in every experiment. Then I've edited heroes again and gave them both different artifacts giving total +22 Defense. Results are the following:

Experiment | Total Damage | Average Damage
A          |    757       |   15.14
A + 22 Def |    753       |   15.06
B          |    743       |   14.86   
B + 22 Def |    745       |   14.9

# of experiments is not that great, but with no way to automate it I don't want to run more :)