Just wanted to give my experiences with this issue:
I bought a refurbished October 2016 style MacBook Pro 13" base model with function keys (MLL42LL/A new, FLL42LL/A refurbished) last week from Apple's website and had it shipped to me in Canada. The laptop was totally pristine, especially the screen and outer case. Definitely not a "used" level product. But within a couple hours of use with streaming video going, the snapping key sound began to appear. At first it was just keys on home row like F and S. I started testing it under a heavier load and more keys began to do it all over the board. Some keys would reliably make the snapping noise 90% of the time and others as low as 10% of the time. That was when I found this thread!
I contacted Apple through the chat support and they were excellent. They booked me a service appointment at an Apple authorized retailer in an effort to get it looked at quickly. When I visited that retailer, the service guy had heard of this problem and had fixed it, but would need to order the replacement parts from Apple ("top case" is the term he used). He suggested I would be better off going to the Apple Store in town and seeing if they would just do a straight swap for a different machine.
At the Apple Store, the service tech was very nice and candid and suggested that the best way to get rid of the keyboard snapping noise would be to return the laptop and buy a similarly priced refurbished MacBook Pro from the previous series, like something in the style of MF839*/A, MF840*/A, or MF841*/A. She described the problem as an unintended feature of the new keyboard design, and any other model I chose in the current range would likely have the same unintended feature. I appreciated the honesty. Unfortunately, being a refurbished product that was shipped from the US, they weren't able to return or exchange the laptop for me right at the store. The laptop is heading back to Apple.
