Just a report guys.
My HTC One was sent in for service on 30th August 2013
I called HTC help line on the 6th September 2013, and they confirm my unit is ready for collection, so I went and collect it.
When I went to collect my unit, no problems on the spot, turn on camera and put it against a stack of papers on the table, pure black. Went home and tested it and ahhh, the problem is back.
Here are some pictures to share, it is a pitch black room, and the only source of light is the LEDs on the air conditioner.
THIS IS WITH THE
FRONT CAMERA
THIS IS WITH THE REAR CAMERA, ULTRAPIXEL
ISO Setting - AUTO

ISO Setting - 100

ISO Setting - 200

ISO Setting - 400

ISO Setting - 800

ISO Setting - 1600

Yes, its almost non-existant @ ISO 100, but if you understand the function of ISO, higher ISO allows you to take pictures in low-light situation with a faster shutter speed. Higher ISO always result in more grainy pictures, not PURPLISH!
I've also tested different white balance setting, the problem doesn't go away, just changes purple tint to blue tint. So as you can see this is not a software issue, its definitely hardware.
I will be dropping by HTC Service Center again this Friday. We will see if this problem get solved first or the Sony Xperia Z1 comes out first. I don't enjoy getting screwed over after paying RM2k+