An unknown but presumably small number of MacBook Air computers appear to be plagued by display problems.

Introduced two weeks ago, the redesigned MacBook Air has been the subject of numerous complaints on Apple's support forum. The computer's screen flickers for some users, as documented in this YouTube video.

"Every so often while using it, the screen has a ton of weird colors in vertical lines ... and the entire laptop has frozen," wrote an person posting to Apple's support forum under the name "DanRyb." "I have to force it off with the power button and reboot it. It happens at random times."

Apple did not respond to a request for comment.

But according to BGR, a tech news blog, Apple has acknowledged the problem internally. The site has posted screenshots from a computer screen that displays Apple support documents. The documents describe two separate issues affecting the MacBook Air -- displays fading upon waking from sleep and flickering.

Several users report receiving replacement MacBook Air units from Apple Stores.

Earlier this year, Apple faced a more significant quality problem with its iPhone 4, a fumble that some believe forced the resignation of Mark Papermaster, SVP of device hardware and engineering. Following the launch of the iPhone 4 in June, reception problems were widely reported. The issue turned into a public relations misstep when Apple CEO Steve Jobs suggested iPhone 4 users could solve the problem by holding their iPhones in a different manner.

Apple eventually responded with a public letter in July stating that the problem was a matter of perception rather than a flaw in its antenna design: The company said that the apparent poor signal strength was the result of a calculation error that showed a weaker signal than was actually available. Nonetheless, the company offered iPhone 4 customers free bumper cases.