Initially I did not have the purple tinge problem. Somehow it came with Android 4.4.2 kitkat update. I did some research on the internet and found, that the image sensor is getting heated up as the camera remains on, even when switched off. So I went to the dealer here in Germany where I bought this phone from. Thank God it was in warranty. No questions asked, they just repaired it for free. They replaced the image sensor which had got damaged. No it has been a year and I don't have any purple tinge.
The phone is good, if you don't care much about the camera. But if you are going to use the camera extensively, then I suggest avoid HTC phones. All have some purple tinge problem. See it for yourself in camera samples taken by people at GSMarena in the indepth review sections for phones like M8, M9, Desire Eye, just to name a few.