Why is my trackpad crackling?

I've got a MBP 15 mid 2015 and its trackpad makes a clicking noise right before the "right clicking sound" when I press it in the upper right part. https://youtu.be/PhqEO0kNGSU I work in a rather silent room and every time I hear this click it drives me crazy. It appears even when the macbook is turned off and the trackpad's supposed to be not clicking at all - but touching it may cause this crackle again. It happens not every time I click the trackpad - it could be gone for an hour after a couple of checking clicks but eventually it returns. It always returns. Resetting smc, cleaning with a paper corner or with compressed air, tightening or untightening the lid screws - none of this helped. We don't have any apple authorised repairs in the town, but even if we had one, they'd laugh in my face because this problem surely would never occur while trying to demonstrate it. Other than that the trackpad is working fine, and this laptop is clean as far as I can see and has never been damaged - it's in mint condition. Am I doomed to listen to this occasional crackle?