Failed side project sat on my resume for two years before someone finally asked about it in an interview

Built a scheduling app for a coworking space that never shipped past a broken beta. Left it on my resume out of laziness more than strategy, one line, no metrics because there weren't any. Finally got asked about it properly in a screen last month, not the shipped stuff, this one. Spent twenty minutes on why it broke, what I'd change now, what I learned about scope creep. That was the most engaged an interviewer's been with anything I said all cycle. Still not sure if I should polish that line up or leave it exactly as unfinished as it actually was.