Platform, device version and operating system: All
Screenshot or image: Look at in-game news - it still says “Spooky Imp - Not long now before our current Imp takes a break.”
What you were expecting to happen, and what actually happened:
That the news was updated since it wasn’t in chests from the end of November.
How often does this happen? When did it begin happening?
I would presume every time, since Spooky Imp should no longer be in chests.
Steps to make it happen again
Open glory/gem/guild/VIP chests.
Basically this information should have been updated, now that Spooky Imp has been replaced by Winter Imp. This is assuming that the normal Imp schedule still applies: