None of the six iPhone Xs in CNET's possession -- including several purchased at retail -- exhibit the green line issue.
Apple did not immediately respond to a request for comment. This issue should be covered by the company's standard warranty, however, and owners have reported that Apple is exchanging iPhone Xs that display the green line for fresh phones.
If your iPhone X goes green, contact Apple Support -- via @AppleSupport on Twitter, online chat, your local Apple Store or your country-specific Apple customer service number -- to report the problem and ask for a replacement. Be prepared to have your order information on hand.
As more consumers get their hands on the iPhone X, Apple's most expensive phone by far, various issues continue to emerge. Electronics warranty company SquareTrade demonstrated theby scuffing and breaking its screen, and CNET's own test unit . Apple has also said that it will address reports of the X having issues while through a future software update.