Last week, Dan Riccio, Apple’s senior vice president of hardware engineering, said in as statement that the AirPower had failed to meet the company’s “high standards” in testing and that it had been canceled before ever being publicly released. Riccio didn’t say specifically why AirPower failed, but several reports over the past year suggested Apple’s desire to make it possible for customers to wirelessly charge their iPhones, AirPods earbuds, and Apple Watches simultaneously wasn’t technically feasible.

In testing, those reports said, Apple’s AirPower would overheat and fail to adequately charge the devices.

The AirPower, which was supposed to be released in 2018, is an embarrassing misstep for Apple, which has typically kept its hardware plans quiet until after it knows a product is ready. Indeed, Apple’s commitment to secrecy is as much about building hype as it is a desire to avoid looking foolish.

AirPower wasn’t a critical product and didn’t permanently damage Apple’s reputation. But it’s the latest in a string of hardware troubles that raise questions about the company’s vetting of new products.

Here are a other recent hardware failures by Apple:

Butterfly Keyboard

Apple’s MacBook “Butterfly” keyboard, so named because it resembles a butterfly’s wings, was supposed to reinvent the keyboard when it was introduced in 2015. But users quickly started complaining about its keys sticking or letters appearing on screen, even when users never pressed the corresponding keys.

In 2018, Apple announced a free repair program to fix the faulty keyboard.

Now in its third generation, the Butterfly Keyboard is still causing users trouble. Just last week, The Wall Street Journal‘s technology columnist Joanna Stern published a column about Apple’s keyboard woes. Her column, which omitted all “e” and “r” letters due to her own faulty Mac keyboard, prompted Apple to issue another statement about the matter and to apologize.

An Apple spokesperson told Stern that the problem affects only “a small number of users” and that the “vast majority of Mac notebook customers are having a positive experience with the new keyboard.”

Antennagate

In 2010, sales of Apple’s iPhone were soaring and the company’s profits were skyrocketing. And then, Consumer Reports said it couldn’t recommend the iPhone 4 because of its problematic antenna.

In what became known as “Antennagate,” Apple customers—and Consumer Reports—said the iPhone dropped a high number of calls when users inadvertently covered a small gap on the phone’s side—where the iPhone’s antenna was located—with their fingers.

Soon after, Apple and its then-CEO Steve Jobs defended the iPhone’s design and said that phones by other manufacturers also had the same problem.

Eventually, Apple created a bumper that fit around the iPhone and created a gap between the antenna and users’ hands. The company designed subsequent phones so that users were less likely to cover the gap and the antenna with their hands.

In the end, the iPhone 4 dropped only 1 in 100 calls, Jobs said at the time. Many Apple fans have used that estimate to suggest that the problem wasn’t as widespread as suggested.

Bendgate

Shortly after Apple debuted the iPhone 6 and iPhone 6 Plus in 2014, some users said that their new devices would bend if they applied enough pressure. Some reported that the iPhone would warp if they accidentally left it in their back pocket while sitting down.

Eventually, the problem gained a name—Bendgate. And before long, people published videos of bendable phones on YouTube and other social media sites. In response, Apple announced a free replacement program for any iPhone 6 or iPhone 6 Plus that had been unintentionally bent.

iPhone Batteries

In 2017, some longtime owners of iPhone 6 and iPhone 6 Plus said the devices had started to sporadically shut down and drain of battery power.

Apple replied by writing a letter to customers apologizing for the problem and explaining that batteries can lose their charge more quickly as they age. The company also acknowledged that it had recently updated its software to do a better job of managing its battery consumption and stop phones from shutting down due to their aging batteries.

But because problems persisted after the software update, Apple said in its letter that it would make battery consumption information more readily available in its iOS software to give users more insight into how much life their batteries had left. Apple also said that it would cut the price for a replacement battery for an iPhone 6 or later phone to $29 from $79.

At the time, Apple didn’t say how widespread its battery woes were. But after the company disclosed the cut in price for replacing phone batteries, customers flocked to Apple Stores. Soon after, because of huge demand, iPhone owners had to wait weeks for their replacement batteries to arrive.