This happen too me yesterday, both me and the caller thoguht the problem was at the callers end but now I`m not sure. I could hear her but she couldnīt hear me. I dontīt think this was the first time I received a call whlie listening too the radio but maybe this was the first time receiving a call while listening too the radio with PR 1.2 installed, just a thought.
My biggest problem with the radio app is that the sound disappears when doing anything with the N900 like surfing the web, recieving a sms or mms, opening another app. Sometimes the sound will come back but most of the times I have too close the radio app and start it up again too make the sound appear.