I have not had the fade away issue at all and I have 16,000 miles on my 2013 with the HUD always turned on. My issue is the radio information fade away. Sometimes it works and sometimes it doesn't. All other HUD info seems to work as designed. Definitely have your cars serviced. This sounds like a fixable issue. If it's possible while you're driving, have your phone cam ready to record the fade away so you have something to show your dealer.
2013 2LT/RS IOM M6 w/DUAL-MODE EXHAUST, BLADE WING SPOILER AND ZL/1 PERFORMANCE PEDALS