Windows Phone 8.1 Xamarin.Forms UI buttons, forms fields and selectors are distorted

I have a pretty basic Xamarin.Forms app (1.4.3.0). The UI looks great on Android and iOS, but it looks terrible on Windows Phone 8.1. The XML is part of the PCL project. The buttons display as thin blue lines that run across the screen. The forms fields appear as thin gray lines that run across the screen and the form drop-down selectors and date picker form fields appear to be cut in half width wise. Please see attached screen shots for specific examples.

Any idea on how to fix this? I read that Xamarin Xaml and Microsoft Xaml are different, but that same article said that differences would be fixed in a Xamarin.Forms version that is earlier that the one I am currently using.

Thanks!