diff --git a/src/resources/extensions/gsd/auto.ts b/src/resources/extensions/gsd/auto.ts
index fe21ed438..f39edba93 100644
--- a/src/resources/extensions/gsd/auto.ts
+++ b/src/resources/extensions/gsd/auto.ts
@@ -1164,8 +1164,9 @@ export async function startAuto(
         s.activeRunDir = meta.activeRunDir ?? null;
         s.originalBasePath = meta.originalBasePath || base;
         s.stepMode = meta.stepMode ?? requestedStepMode;
+        s.autoStartTime = meta.autoStartTime || Date.now();
         s.paused = true;
-        try { unlinkSync(pausedPath); } catch { /* non-fatal */ }
+        try { unlinkSync(pausedPath); } catch (e) { logWarning("session", `pause file cleanup failed: ${e instanceof Error ? e.message : String(e)}`, { file: "auto.ts" }); }
         ctx.ui.notify(
           `Resuming paused custom workflow${meta.activeRunDir ? ` (${meta.activeRunDir})` : ""}.`,
           "info",
@@ -1197,21 +1198,24 @@ export async function startAuto(
             s.pausedSessionFile = meta.sessionFile ?? null;
             s.pausedUnitType = meta.unitType ?? null;
             s.pausedUnitId = meta.unitId ?? null;
+            s.autoStartTime = meta.autoStartTime || Date.now();
             s.paused = true;
-            try { unlinkSync(pausedPath); } catch { /* non-fatal */ }
+            try { unlinkSync(pausedPath); } catch (e) { logWarning("session", `pause file cleanup failed: ${e instanceof Error ? e.message : String(e)}`, { file: "auto.ts" }); }
             ctx.ui.notify(
               `Resuming paused session for ${meta.milestoneId}${meta.worktreePath && existsSync(meta.worktreePath) ? ` (worktree)` : ""}.`,
               "info",
             );
           }
         } else if (existsSync(pausedPath)) {
-          try { unlinkSync(pausedPath); } catch { /* non-fatal */ }
+          try { unlinkSync(pausedPath); } catch (e) { logWarning("session", `stale pause file cleanup failed: ${e instanceof Error ? e.message : String(e)}`, { file: "auto.ts" }); }
         }
       }
     } catch (err) {
       // Malformed or missing — proceed with fresh bootstrap
       logWarning("session", `paused-session restore failed: ${err instanceof Error ? err.message : String(err)}`, { file: "auto.ts" });
     }
+    // Guard against zero/missing autoStartTime after resume (#3585)
+    if (!s.autoStartTime || s.autoStartTime <= 0) s.autoStartTime = Date.now();
   }
 
   if (!s.paused) {
diff --git a/src/resources/extensions/gsd/guided-flow.ts b/src/resources/extensions/gsd/guided-flow.ts
index 451a9011c..7ba292d38 100644
--- a/src/resources/extensions/gsd/guided-flow.ts
+++ b/src/resources/extensions/gsd/guided-flow.ts
@@ -1314,8 +1314,8 @@ export async function showSmartEntry(
     if (interrupted.pausedSession) {
       try {
         unlinkSync(join(gsdRoot(basePath), "runtime", "paused-session.json"));
-      } catch {
-        // Non-fatal stale metadata cleanup.
+      } catch (e) {
+        logWarning("guided", `stale pause file cleanup failed: ${(e as Error).message}`, { file: "guided-flow.ts" });
       }
     }
   } else if (interrupted.classification === "recoverable") {
diff --git a/src/resources/extensions/gsd/interrupted-session.ts b/src/resources/extensions/gsd/interrupted-session.ts
index 5dae6f52c..8c6274a05 100644
--- a/src/resources/extensions/gsd/interrupted-session.ts
+++ b/src/resources/extensions/gsd/interrupted-session.ts
@@ -33,6 +33,7 @@ export interface PausedSessionMetadata {
   unitId?: string;
   activeEngineId?: string;
   activeRunDir?: string | null;
+  autoStartTime?: number;
 }
 
 export interface InterruptedSessionAssessment {