Some bugs are silent because the thing protecting against them is doing exactly its job.
A self-repair that assumed too much
Older accounts’ configuration gets upgraded automatically, so fixes accumulated over months are applied retroactively, not just baked into new accounts. The mechanism cuts off the old version of a section and writes a fresh one in its place.
Cutting cleanly requires knowing exactly where the old version starts. The measurement used a fixed assumption about layout, true for every configuration the panel writes for itself but not for one that predates the mechanism. On one older configuration the cut landed slightly off.
Why nothing actually broke
Every repair attempt here validates its own output before committing to it, and reverts immediately if that check fails. The mis-measured cut did fail it, every time — a dangling, unclosed block is not valid configuration by any definition — so the safety net caught it, restored the original file, and moved on. The site stayed up, the whole time, correctly. What didn’t happen was the actual repair: the newer fixes that should have reached that configuration never did, because the attempt kept failing at the first step.
It was found by reading the logs rather than assuming a quiet system is a healthy one.
What actually shipped
The fixed assumption is gone; the repair now finds the real edge of the section wherever it is. Verified against the previously failing configuration before it went near a live server again: the repair completes, and that configuration now has the same fixes every newer one already had.