Problem on XF 1.5 with standard Picker control not rendering completely

I am using standard Picker controls in my iOS app. They sometimes misbehave, by not rendering the Done button.

See the attached screenshot.

This issue has been present since XF 1.3 I use Picker controls on 3 pages, and the issue occurs everywhere, but is more prevalent on the most complex page.

I am using ManateeWorks Barcode SDK as well, and am wondering if that might have an impact ito threading perhaps?

Has anyone else come across this?

Win 7 64
VS 2013
XF 1.5.1
Build Service 4001689
XCode 7