You may envy those who have their hands on a Desire HD already, but early-adoption is rose-like with its obligatory thorns attached. Many owners on XDA-Developers are reporting issues with their phone's screen when making and receiving calls. Outbound calls appear to deactivate the screen permanently and render the phone entirely unresponsive, save for a battery-pull and fresh boot. Receipt of calls conversely keeps the screen on and active, even when pressed against your ear.
The issue seems to be tied to the light-sensor , with some users noticing their device not experiencing the aforementioned problems in brightly-lit conditions. It seems like a buggy software implementation which should be quite easily fixed with an OTA, but it is unfortunate to see the device shipping with this misbehaviour included.
Thankfully users have discovered a temporary a work-around for the inert state the phone enters when making a call: inserting a headset into the headphone jack wakes the phone from its previously locked condition.
Follow the thread below for any further developments.