This hasn't happened to me yet. Sometimes, however, I can't unlock my phone as the screen won't turn back on...I don't think I've had a phone call while experiencing this, however. A restart seems to fix it, so I guess it's software-related.
I get this too, rarely so far. Happend twice on about 400 phone calls. Does it go like half way, no matter how far you slide your finger???? thats what happens to me, software fix will sure this up, not an issue though since it never made me miss a call!