Apple’s 2016 MacBook Pro not only came with a new Touch Bar, but also a revamped keyboard which featured the second-generation butterfly mechanism. Unfortunately, there’s a growing number of users experiencing problems with the MacBook Pro’s keyboard.

Some 2016 MacBook Pro users have reported several issues with their keyboards, including non-functional keys, high pitch noise on some keys and keys with non-uniform feel, according to MacRumors. The news site also noted that there are dozens of forum threads on its website involving these issues, as well as on Apple’s Support webpage.

Users are reporting that certain keys on the 2016 MacBook Pro would enter double letters or remain unresponsive. This has been echoed by several other MacBook Pro owners as well. It remains unclear what’s causing this issue, but it may be due to the new butterfly mechanism simply being less reliable.

The first-gen butterfly mechanism was first introduced by Apple back in  2015 for its 12-inch MacBook.  The design allowed Apple to make the laptop extremely thin, while also providing enough keyboard travel when typing.

The butterfly mechanism received mixed reviews from fans and critics, and it’s often been cited as feeling “squishy” or “spongey” instead of a more satisfying click. For the 2016 MacBook Pro, Apple improved the feel of the butterfly mechanism keyboard. 

The issue that seems the weirdest is the high-pitched noise produced by some keys. This was demonstrated by a user named monstermac77 on his 15-inch 2016 MacBook Pro. His video shows that the click sound produced by the caps lock key is strangely louder compared to the shift key.

Monstermac77 says that the problem may have been caused when the MacBook is warm. Other affected keys include left option, delete, H and C.

There are several other complaints shared by numerous other 2016 MacBook Pro users with varying sizes/models. However, the problems appear to be more common on the 15-inch MacBook Pro, according to Digital Trends.

Currently, the only real way to get these problems checked or fixed is to bring the affected MacBook Pro unit to a nearby Apple authorized service provider. Replacing a keyboard may take a few days as the process is not as simple as in previous models.