[REJECTED] [PVE] Mythic dungeon key, bosses doesnt count, but mobs are

[jokehold]

Bug description: 2-3 days ago doing Arcway m5 the boss counter didnt count ( after killing bosses counter was still 0/1), but mobs did count. Image below.
Yesterday same thing happened 2 times in a row with the same instance, DHT. We were doing m2 key and m3.
M2 we did in raid, but m3 in party .
Proof: https://imgur.com/a/Vt2rljk



In the Arcway dung were 4 of my friend, in DHT 5 of my friend. So, in my opinion, it could be:
1) ilvl related (880+,870+, 830, 832, 856).
2)Main thought is that one of us didnt open world quest
3)Didnt check if we were all Horde or Allies, because 1 of 5 was Horde.

Feel free to ask any question
Saw 2 or 3 post about this problem but it was rejected without any answer, so looking forward to hear what causing this or how to avoid it.
One of the posts https://forum.wow-freakz.com/REJECTED-Mythic-Keystone-Bugged-t528678.html

[jokehold]

Today's mythic keys!
Same thing
https://imgur.com/a/Knmi33N m5
https://imgur.com/a/dx0fJmF HoV m2