Goodhart’s Law really only applies to measures that aren't measuring the actual figure of merit but a proxy that is incorrectly assumed to be inextricably tied to it.

This is very common, though, and a real problem associated with it is people pick proxies without clearly documenting (or even thinking through) what they want to measure, why they pick a particular proxy, and how the proxy might fall. As a result, people remote from the decision (including the original decision maker) tend to incautiously apply the proxy because they aren't even aware that it is not the actual figure of merit.