I've finished the mission after switching to the android version of RAID. But still concerned that similer missions (e.g. other potion keep and dungeon missions that require certain drops) may be bugged in the future. Will try to report future progress in this thread.

Hi,

I do believe sometimes this quest can lag in showing completion, but you can also contact support directly and see if they can take a look to figure out if it just didn't register on one device/platform/OS (which would be very weird)