fix: bug where parser incorrectly preserves both DLE and XX

parsers/s3_parser.py

@@ -321,13 +321,8 @@ def parse_bw(blob: bytes, trailer_len: int, validate_checksum: bool) -> List[Fra
             i += 1
             continue
 
-        # AFTER_DLE
+        # AFTER_DLE: DLE XX => literal XX for any XX (full DLE stuffing)
-        if b == DLE:
+        body.append(b)
-            body.append(DLE)  # 10 10 => literal 10
-        else:
-            # Robust recovery: treat as literal DLE + byte
-            body.append(DLE)
-            body.append(b)
         state = IN_FRAME
         i += 1