Troops missing in arena again

Platform, device version and operating system

What you were expecting to happen, and what actually happened
I expect the newly released troops to be added to the pool of the troops available for arena and they are not.

How often does this happen? When did it begin happening?
No troop has been added since I submitted a ticket for the same reason after Merlantis was released. So the troops of Bright forest and Shentang and all the troops released after Merlantis, starting with the Bat warm, are missing in arena.