Maybe it's just some UK channels?
Right now on BBC1 ... "Morning Live" I'm getting "Dolby Audio - DD" sent to my Denon AVR.
When I select "watch from beginning" - hence using Replay - I get "PCM" sent to my AVR.
I tried with SRF 1 (Rosamunde Pilcher, EP110) and that seems fine! Dolby Digital/Surround on live and replay.