We have confirmed that there has been an issue in the 10x Rank EXP in Select Descended Dungeons bonus of the How to Train Your Monsters Event.
The issues consisted of Borma Descended! and Zapan Descended! not providing first-time clear rewards properly, as well as an issue where players who have already cleared the dungeon in the past have been seeing the NEW sign on the dungeon selection screen.
As a result of the dungeons not working as intended, the affected dungeons will be available for the following durations. Please note that the contents will be unchanged and rewards of these dungeons will be obtainable as intended:
[Duration]: 9/17, 0:00 - 23:59 (UTC-8)
[Duration]: 9/18, 0:00 - 23:59 (UTC-8)
See here for more details regarding the How to Train Your Monsters Event: https://bit.ly/3R9EFm8
We sincerely apologize for any confusion and inconvenience this may have caused and thank you for enjoying Puzzle & Dragons.