Vision Pro owners have reported mysterious cracks in their windshields.

Vision Pro owners have posted nearly similar reports of cracks appearing on the front glass of their headsets. None of them seem to know how it happened.

This problem was first discovered by mcroomers, and so far there are five Redditors who have posted about it on the r/VisionPro subreddit. What’s interesting is that in all the photos uploaded, a vertical hairline crack can be seen in the exact same area above the bridge of the nose. All of the affected Redditors said they had not done anything overt to cause the cracks, such as dropping the device or storing it improperly. Reddit user @dornbirn claims he polished the front glass, covered it with a soft cover and put it away in the case, only to wake up the next morning to find it cracked. Most of his other affected Redditors also said they kept their Vision Pro in a case or had a soft cover on it.

Some speculate that this may be due to a heat generation issue when charging the Vision Pro while it is in the case or with the cover on. Some argue that it’s a manufacturing issue with the glass, or simply a design flaw that puts too much tension in certain areas.

It’s also unclear if the hairline crack is just a cosmetic issue, as it appears to appear above the sensor but isn’t interfering with any of the cameras. That said, Vision Pro repairs are expensive. If you subscribe to Apple Care (which costs him $500 for the Vision Pro), there is a $299 deductible for damage to the cover glass. Without it, it costs $799. @ContributionFar8997 wrote that he went to the Apple Store and was told he would have to pay a deductible to have the crack fixed.

So far, reports seem to be limited to Reddit, so it’s unclear how widespread the issue is. The Verge Apple did not immediately respond to a request to ask if it was aware of the issue.