Was the announcer recording links for Radio 3 perchance?
Sounds like she was recording links for later on, one was for the Sign Zone (and they're not anything like the style Radio 3 uses!). I can understand her getting faded up erroneously but I'm surprised how long it took her to realise the channel's in a breakdown
Poor form from the Network team IMO - far too long for someone not to realise the error, this is primetime BBC Two. Worth noting that NI pulled her sound when she started reading Sign Zone links, did their own apology, and only faded Network sound back up once the music was on air.
Meanwhile Scotland - Tony Currie by the sound of it, ever the professional - put up their own local slide and music, and gave a very thorough running explanation of the nature of the technical problems - even playing a symbol into Coast. Wales sat back and let Network embarrass themselves.