diff --git a/internal/api/acme/validators.go b/internal/api/acme/validators.go
index 76fbbae..286a1e2 100644
--- a/internal/api/acme/validators.go
+++ b/internal/api/acme/validators.go
@@ -191,8 +191,9 @@ func (p *Pool) Drain(ctx context.Context) error {
 	}
 }
 
-// Snapshot returns the current per-type in-flight + peak counts. Used
-// by chaos tests to verify the configured weights were never exceeded.
+// PoolSnapshot is the per-type in-flight + peak observation set used by
+// chaos / concurrency tests to verify the configured weights were never
+// exceeded.
 type PoolSnapshot struct {
 	HTTP01InFlight    int64
 	HTTP01Peak        int64
@@ -202,6 +203,7 @@ type PoolSnapshot struct {
 	TLSALPN01Peak     int64
 }
 
+// Snapshot returns the current per-type in-flight + peak counts.
 func (p *Pool) Snapshot() PoolSnapshot {
 	return PoolSnapshot{
 		HTTP01InFlight:    p.http01InFlight.Load(),
diff --git a/internal/service/acme.go b/internal/service/acme.go
index 326667c..6062c84 100644
--- a/internal/service/acme.go
+++ b/internal/service/acme.go
@@ -1235,10 +1235,11 @@ func (s *ACMEService) RespondToChallenge(
 	}
 
 	// Submit to the pool. The onComplete callback persists the final
-	// challenge status + cascades the parent authz status. We use a
-	// fresh background context here so the callback's WithinTx isn't
-	// canceled when the originating HTTP request returns.
-	bgctx := context.Background()
+	// challenge status + cascades the parent authz status. We detach
+	// from the request context via context.WithoutCancel so the
+	// callback's WithinTx survives the HTTP handler returning, while
+	// preserving inherited values (logger, trace IDs, audit actor).
+	bgctx := context.WithoutCancel(ctx)
 	chSnapshot := *ch
 	authzSnapshot := *authz
 	identifier := authz.Identifier.Value