There was a submission here a few weeks back about ShitSpotter and how they seem willing to put in overrides at request of the police without necessarily having a basis for it.

If that's what happened in this circumstances it would be, police check ShoySpotter for more evidence, ShotSpotter hasn't automatically marked anything, police request manual review for gunshot they are sure must be there, ShotSpotter manual review process comes up with something and marks it as a shot with a human override.

There's a lot of places bias, or outright corruption, could cause problems in that process, if it's what happened here.