There was a trick to remove the shadow on navigation bar. It consisted on set a image of the same color as the background and set it to barImage property and set hideShadow to true.
It is working with 8.2.0.GA on iOS 13 < but not on iOS 13.
This line could be related with:
On the screenshot attached:
- iOS 13 on the left side.
- iOS 12 on the right side.