diff --git a/src/lib/db.ts b/src/lib/db.ts
index 5a30722..f935863 100644
--- a/src/lib/db.ts
+++ b/src/lib/db.ts
@@ -126,14 +126,14 @@ export function upsertAlerts(candidates: AlertCandidate[]): number {
 
       if (isSuppressed) continue;
 
-      // Re-open if previously closed (manually or resolved) and not suppressed
+      // Re-open if previously closed (manually or resolved) and not suppressed.
+      // Preserve firstSeen and comments — this is the same incident continuing,
+      // not a brand new one.
       if (existing.status === "closed") {
         existing.status = "open";
         existing.closeReason = null;
         existing.closedAt = null;
         existing.suppressedUntil = null;
-        existing.firstSeen = nowISO; // treat as a new occurrence
-        existing.comments = [];
       }
 
       // Refresh content and lastSeen