diff --git a/src/main/download-manager.ts b/src/main/download-manager.ts
index e0b72b2..3bae838 100644
--- a/src/main/download-manager.ts
+++ b/src/main/download-manager.ts
@@ -1029,7 +1029,14 @@ function hasSceneGroupSuffix(fileName: string): boolean {
 
   const fallbackMatch = text.match(SCENE_GROUP_SUFFIX_FALLBACK_RE);
   const suffix = String(fallbackMatch?.[1] || "").trim();
-  return isValidSceneGroupSuffix(suffix);
+  if (isValidSceneGroupSuffix(suffix)) {
+    return true;
+  }
+  // Auch Scene-Gruppen MIT Unterstrich erkennen (z.B. "-idTV_iNT", "-NZ_iNT", "-DUBBED_iNT").
+  // Sonst wird ein sauber benannter Episoden-Ordner wie "Castle.S08E02.GERMAN.DL.720p.WEB.H264-
+  // idTV_iNT" faelschlich NICHT als Scene-Ordner erkannt → die Namensherleitung faellt auf den
+  // obfuskierten Paket-Ordner ("scn2-cstl7") zurueck und verschlimmbessert den Namen.
+  return extractFlexibleSceneGroupSuffix(text) !== null;
 }
 
 /** Older scene releases used "1x01" instead of "S01E01". The episode group
diff --git a/tests/auto-rename.test.ts b/tests/auto-rename.test.ts
index fb14d69..81b7b82 100644
--- a/tests/auto-rename.test.ts
+++ b/tests/auto-rename.test.ts
@@ -112,6 +112,22 @@ describe("decideAutoRenameBaseName (shared naming decision — used by auto-rena
     );
     expect(decision.kind).toBe("skip");
   });
+
+  it("uses the CLEAN per-episode folder (scene group WITH underscore, e.g. -idTV_iNT) — not the obfuscated package folder", () => {
+    // User-Report v1.7.178: castle.s08e02....mkv im sauberen Ordner "Castle.S08E02...H264-idTV_iNT"
+    // (Paket: "scn2-cstl7") wurde zu "scn2-cstl7.S08E02" verschlimmbessert, weil hasSceneGroupSuffix
+    // die Unterstrich-Gruppe "-idTV_iNT" nicht erkannte und auf den Paketordner zurueckfiel.
+    const epFolder = "Castle.S08E02.GERMAN.DL.720p.WEB.H264-idTV_iNT";
+    const decision = decideAutoRenameBaseName(
+      [epFolder, "scn2-cstl7"],
+      "castle.s08e02.german.dl.720p.web.h264-idtv_int.mkv",
+      "castle.s08e02.german.dl.720p.web.h264-idtv_int",
+      epFolder,
+      "scn2-cstl7"
+    );
+    expect(decision.kind).toBe("rename");
+    expect(decision.kind === "rename" && decision.baseName).toBe(epFolder);
+  });
 });
 
 describe("hasMeaningfulSeriesPrefix", () => {