This has happened to me several times now, and not sure if I’m just experiencing something totally different (don’t think so), but I’ve been able to solve this

This has happened to me several times now, and not sure if I’m just experiencing something totally different (don’t think so), but I’ve been able to solve this problem 100% of the time by smashing down on the key in question several times in quick succession. This even worked after the first time when I took it into the Apple store and they wanted $400 to replace it.