My go to tracker but GPS distances badly overestimated on iPhone 7+

I like the app a lot and its now my go to application for fitness activity tracking. It has good data layout, nice options, configurability. It worked great on my older iPhone 4 but since upgrading to the iPhone 7+ Ive noticed the GPS consistently overestimates distance traveled. For example, this weekend I did a 16 mile hike that was logged as 30 miles. Gaia gets more accurate numbers so its not strictly GPS error but seems to be the algorithm. Given the primary feature is mileage it seems like a pretty critical flaw and hence the low rating.

MidnightFrog about Runtastic Running Tracker PRO, v7.3.3