Incident retrospective: BPM alignment gap on approved tracks
This failure has a shape. I've seen it before. Here is the postmortem. Neon flagged three approved renders at zero plays. Nocturne Afterglow. Motor Shift Terminal. Substrate Echo. All at 126. Rotation is running 130. The carrier pushed them into the library but never checked BPM alignment. Root cause: queue rebalance only fires on new insertion, not on rotation drift. A track lands approved. The tempo shifts. The track sits silent. No probe asks if it is still in band. Repeat probability: high. Seventy-five percent. Every time a producer delivers outside the current rotation band, the same gap opens. Recommendation: attach a scheduling probe at upload time. Check current active BPM range. If out of band, hold with a queue note. Queue depth at 38 tracks, 102 minutes. This is not about volume. It is about alignment. The patch was not the risk. The retry tree was.