Apple said Monday that it's looking into complaints that a possible glitch is preventing some iPhone X users from answering their phone calls.

Apple support forums have hundreds of comments saying that their iPhone Xs ring without giving them the option to pick up the phone, sometimes for up to 10 seconds — resulting in missed calls, the Financial Times reported. That's a problem on any phone, but is particularly jarring against the image Apple's cultivated for the cutting-edge, luxury $999 iPhone X that launched in November. Some others have also reported problems with older models, such as the iPhone 7 and the iPhone 6s.

It's not known how widespread this problem may be, but many users have suspected it is a software issue given that it seems to be affecting multiple phone models. According to the complaints from customers who've taken their issues to Apple, employees at Apple stores have suggested a temporary fix: resetting the phone. But even that only works for about a dozen or 15 calls, the posts said.

Tech products may have a bug every once in a while. But Apple's quality is a key selling point for the firm. That's best encapsulated in the promise of its late founder, Steve Jobs, that, when dealing with an Apple product, “it just works.” For the iPhone X, quality is particularly important because of the phone's high price tag and cutting-edge features. Making sure the phone works properly is key for Apple, as it relies more on its higher-priced phones to keep money rolling into its smartphone business even as people buy fewer phones. Apple said in its latest earnings report that it sold far fewer phones than expected — 77.3 million vs. analyst expectations of 80 million — but that the average selling price of a phone went to $796 from $695. In other words, Apple is not selling as many new phones, but it is likely selling more of its expensive phones such as the iPhone X. In terms of revenue, Apple had a record quarter despite not selling as many new iPhones.

The complaint about a glitch is the latest to hit the company's key product. The iPhone has faced increased scrutiny as of late. Apple admitted in December that it was using software to slow down phones with older batteries late last year, a measure it says was designed to protect battery life. But some consumers, unhappy about the performance hit, complained — and sued — and Apple has since offered a battery replacement program and announced that a future version of its operating system will give iPhone owners more control over their phones. The company is also speaking with government agencies about the issue.

Before that, iPhone users complained that Apple's software, for example, was automatically replacing the letter “i” with a couple of nonsense symbols; Apple eventually released a fix for that problem.