I have run into an issue with getting Drillthrough to work on the Power BI Mobile App.
I created the reports and views (both web and mobile) on Power BI Desktop. Report is 5 pages, with the first page drilling to the second, the second drilling to the third, and the third drilling to the fourth or fifth. The first page drills on the region manager names, the second is the region manager and can drill on the area manager, the third is the area manager and can drill on the store number to access one of two pages.
Drillthrough on the .pbix file works as expected.
I upload the file to the Power BI Service. I tested (and recreated) the drillthroughs from the web service view. This works as expected.
I open the Power BI Mobile App on my iPad mini (Power BI Mobile App version 17.2 listed). The mobile view created on the original .pbix file comes up. I then perform long-taps on the 1st page of the report, and get a tooltip but no arrow for drillthroughs. I repeat this on the second page, with the same result. On the third page, the area manager with store numbers to drillthrough on, only some of the visuals allow me to get the tooltip with the arrow to drillthrough (when they do show up, I do get the choice of the two last pages, so that is working correctly). Drillthroughs were setup on each page the same way, and the hierarchy it is drilling on is consistent on each page.
My clients are looking to roll this report out to some 500 users in the next week or two, and having this capability is vital.