| | Helloooo...
I was logging on to post this issue today and here it is with much commentary.
I am having the same landscape / portrait issue. I hit the answer in landscape and the phone stops ringing and stalls. Then I rotate to portrait to talk and the phone rings again. I hit the answer button and silence again. Missed call....ugh!!
The phone does this during operations too when you rotate the phone. Additionally, if you are texting and get a call, good luck. I have never gotten it to answer. I think a fix should involve the phone alerting you to an incoming call in the primary operation and offer an alternate answer or reject pop up.