Update:
Yes, that's one of the issues I had.
The issue is how the keyboard's designed, there's a metal piece underneath the keys that produce a popping sound sometimes when the laptop's warm. I had a similar problem in addition to a faulty key which double typed the letters or sometimes didn't type anything at all. I eventually scheduled an appointment with the Apple Store Genius Bar and they shipped it out for repair.
I got the unit back with a different keyboard, 2017 model and I have not had this problem since. So having it repaired is my main suggestion to you. It took Apple 6 days to get it back to me and I live in Hawaii.
If you want to test the heat issue, download and install smcFanControl and set the fans to run at a speed to keep your temps down. If you notice that the popping sounds disappear, then that's what I was describing. But in the end I will still suggest you have it repaired for a more permanent fix. Hawaii's quite warm all year long, so a heat related problem will show up often for me.
I hope this helps.