Nokia admits presence of Lumia 710 disconnect glitch
Nokia has responded to the claims and is aware of the problem. The good news is, Nokia is assuring everyone that the phone modem is, in fact, disconnecting the call and glitch is occurring with the display, so no monthly minutes will go to waste.
As far as a fix, there is no ETA at this time, however, Nokia states that it is “close to a fix.” Hopefully that translates to sooner rather than later.
source: Nokia Support via MobileBurn