Since the 2015.3 upgrade I've run into a strange issue where any Standard Def PAL (720x576) Pro Res 422 export won't work if the source footage is also SD PAL Pro Res 422.
The export takes forever and once exported all I get is a Red screen.
Also if I render any SD Pro Res sequence and export using Previews it also doesn't work.
If I add an adjustment layer with a Video Limiter on it (causing the timeline to allow rendering) and export without using previews it works fine.
This same error occurs when using Media Encoder.
All other exports work fine, even when using the same source footage.