diff --git a/source/sw/src/game.cpp b/source/sw/src/game.cpp
index 3cb9c0a8d..a07b02303 100644
--- a/source/sw/src/game.cpp
+++ b/source/sw/src/game.cpp
@@ -370,6 +370,11 @@ void InitLevel(MapRecord *maprec)
         // clear accidental one-sided flag off yet another key card.
         if (sprite[333].picnum == 1774 && sprite[333].cstat == 81) sprite[333].cstat &= ~64;
     }
+    if (!maprec->labelName.CompareNoCase("$outpost") && !maprec->name.CompareNoCase("$TXTS_MAP09"))
+    {
+        // clear accidental one-sided flag off yet another key card.
+        if (sprite[442].picnum == ST1 && sprite[442].hitag == 1002 && sprite[442].lotag == 31) sprite[442].lotag = -1;
+    }
     SECRET_SetMapName(currentLevel->DisplayName(), currentLevel->name);
     STAT_NewLevel(currentLevel->fileName);
     Player[0].angle.ang = buildang(ang);
diff --git a/source/sw/src/sounds.cpp b/source/sw/src/sounds.cpp
index 85afbfdc3..6fdbcc90b 100644
--- a/source/sw/src/sounds.cpp
+++ b/source/sw/src/sounds.cpp
@@ -249,8 +249,11 @@ void InitAmbient(int num, SPRITEp sp)
     // Ambient sounds need special treatment
     if (num < 0 || num > MAX_AMBIENT_SOUNDS)
     {
-        sprintf(ds, "Invalid or out of range ambient sound number %d\n", num);
-        PutStringInfo(Player + screenpeek, ds);
+        if (num != -1) // skip message for -1 to allow using it for silencing buggy ambient sound sprites (there is one in SW level 9.)
+        {
+            sprintf(ds, "Invalid or out of range ambient sound number %d\n", num);
+            PutStringInfo(Player + screenpeek, ds);
+        }
         return;
     }
     auto vnum = ambarray[num].diginame;