One of the most-talked about features of Apple’s upcoming iPhone X — “Face ID,” which allows a user to unlock their phone by looking at it — is causing a headache for the company: Issues with the facial recognition system are reportedly slowing down production, and could translate into widespread shortages when the high-end phones finally go on sale.

Two components, both alike in dignity…

According to insiders who spoke to The Wall Street Journal, the trouble is centered on a pair of facial recognition components dubbed Romeo and Juliet.

The Romeo component uses a laser to beam infrared dots onto the user’s face to map unique characteristics, while the Juliet module reads the pattern with an infrared camera.

Apparently it takes longer to assemble the Romeo modules than the Juliet modules, and as a result, there weren’t enough Romeos to pair up with all of the Juliets sitting around, causing the whole production process to slow down.

One of the sources says the Romeo assembly process is now moving along. Apple declined to comment to the WSJ.

Looming shortages?

While there are usually some supply shortfalls, one of those “folks familiar with the matter” says this may all lead to a bigger than usual shortage on Nov. 3 when the $1,049 phone starts shipping to customers.

Any shortages could set off a ripple effect that may last into the holiday season, potentially pushing shoppers toward other phones.

“If iPhone X availability issues persist beyond November 15 and into the holiday season, we could see some frustrated iPhone users consider switching to other offerings,” one analyst said in a recent note.

Troubles past

This isn’t the first hiccup in the iPhone X production process, either: The phone didn’t join its siblings — the iPhone 8 and iPhone 8 Plus — in going on sale last week partly because of issues this summer with its screens, the WSJ notes.

Face ID also didn’t perform that well during its coming-out party at the Apple launch event earlier this month, refusing to unlock fully during a demonstration. That was because the feature had been accidentally disabled before the event, Apple said later.

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