diff --git a/problem_tracker.md b/problem_tracker.md
index 443e90d3dfd..21d42e0c52b 100644
--- a/problem_tracker.md
+++ b/problem_tracker.md
@@ -241,4 +241,4 @@ We now have a concrete reproduction. To maximize the chance of fixing Zurich's p
 
 The issue was caused by hitting the database on every request when Prometheus was used as a callback. Commit `30534d7e82` fixes this by setting `check_db_only` to `False`.
 
-### Baseline latency spikes
+> It was hard to diagnose because Prometheus was catching database errors and only logging them at debug level. Fixed by commit `d37796662` (adds `_log_budget_lookup_failure` to surface errors). This error is very important—it stops the cache from working properly.
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