This wasn't "not telling the bad one that wasn't needed" -- it was "reviewer (who is our engineering manager for that department) liked him, and put notes to that effect in his file, and the next step is supposed to be in-house recruiter following up to do the next interviews". The in-house recruiter didn't get the note, and there was no internal feedback loop to say it had been stalled. We actually hired a (great) engineer on the data team after he followed up on a post like this months ago; I'm aware the process is broken, and we're trying to improve it.)

We use jobscore. I really wish we used lever.co to track this stuff instead.

On the teams where I am more involved in hiring (i.e. not SRE), we separately track candidates after initial screening using Jira (which we use for everything else), so people don't get dropped.