Platform, device version and operating system:
Windows 10, Steam.
Screenshot or image:
What you were expecting to happen, and what actually happened:
The first picture seems to suggest that we get Emeralds as rewards from these Challenge Tier VIII battles, but the second picture shows that we get Topazes.
How often does this happen? When did it begin happening?
This happened to me in all Challenge batttles in Pan’s Vale. Not sure if it happens in all kingdoms, and is supposed to be random. I’ll update after a bit of a check.
Steps to make it happen again
Just play Tier VIII challenge battles in a kingdom and hope to make it happen again, I guess.