If you’re running mobile applications on iOS 9+, using OutSystems Now or Safari, you might be experiencing slow (~30 seconds) page transitions in your applications.

On iOS9+, Apple changed the way web applications are loaded, in particular font resources. We still don’t know the nature of this change - the issue has been reported to Apple - so while there is no official fix, we suggest you update your applications to use web safe fonts, such as Arial.

The issue occurs on both Safari and applications using web views - OutSystems Now. While retrieving all page resources, the browser sometimes stalls on a font file for around 30 seconds.
Good News!
The latest version of iOS, 9.3, addresses this problem. Applications don't hang as long on resources. Although it still noticeable some leg, it's not as problematic.