maybe.... the sensor for the stylus is dead in the corner? considering your finger touch is still recognized, that's the only thing coming to mind. Since you're not claiming that the stylus has other issues with other parts of the screen i'd assume the stylus is fine as well. I'd guess that this is something that needs to be looked into using more technical instruments like x-rays or high magnifying microscropes or such... could be just hairline fractures causing faulty sensory