Platform, device version and operating system:
Steam; PC/Win7
Screenshot or image:
What you were expecting to happen, and what actually happened:
When defeating Mini-boss in explore results in Arcane traitstone drop, there is also another random traitstone awarded (pictures 1&2; both show Aracane+minor, though, but I’ve witnessed every possible Arcane + “other traitstone” combination).
I was expecting every drop to be just a single traitstone like with non-arcanes (picture 3).
Additionally, on very rare occurrences there is just one Arcane trainstone dropping (picture 4; I witnessed one such instance over the weekend in a little above 2000 explore battles (discounting mythic boss) what makes about 400 Mini-boss battles).
I checked only explore difficulty 3-5-12 and some 10 kingdoms, but one would assume it happens on any difficulty in any kingdom.
How often does this happen? When did it begin happening?
I noticed it happening in Mini-boss battles during vault event last weekend, but it’s plausible that things have been like this for longer.
As far as I remember, it has always worked this way in Mythic boss battles
but I never paid it special attention assuming that it was the case of a random traitstone as per normal battle rewards plus the guaranteed Arcane as per Mythic boss rewards.
I have never noticed double traitstone drops on explore battles 1-4 (pre-Mini-boss battles).
Steps to make it happen again
Play explore.