The API declares the wrong dungeon as the weekly pinnacle on a regular basis. It's probably wrong more often than it's right. This week, for example, the weekly dungeon is Shattered Throne, but on DIM it shows Pit of Heresy.
This has been reported to 3rd party developers like the DIM team many times and they report back that the issue is with the API, not on their end. This has been ongoing for the better part of a year at least. API team needs to double-check their work.