The team looked into this, and there was also bug. Fixed up the terms it was searching against, to what they should be searching against.
We do not use those terms anymore it seems, so not sure if a article will be helpful..
As for the late achievement for 4.0, this is purely because, at the time, we were not able to add any in due to an issue. So, we have added it in later. In no way is it a calculated move to “make” players spend Crowns to unlock the Season, to get the Goal now.. rather than just waiting till the Season is available for Gems (if you didn’t already play through the whole Season).
Also, if you already completed Chapter 3.. you don’t need to do it again to get the trophy.