Platform, device version and operating system
What you were expecting to happen, and what actually happened
I expect the delve during event to be quite exactly the same as the normal delves. So, I also expect the event delves yield the same amount of hero XP as the daily delve
How often does this happen? When did it begin happening?
Steps to make it happen again
Play a battle in daily delve and check your earned hero class XP: 1
Play a battle in delve event and check your earned hero class XP: 2
P.S.: I expect the daily delve XP should be corrected 2, because all limited game modes (dungeon, pet rescue, guild events, class events, etc) yield 2 XP