diff --git a/kitty_tests/parser.py b/kitty_tests/parser.py
index e398e5feb..aa8352135 100644
--- a/kitty_tests/parser.py
+++ b/kitty_tests/parser.py
@@ -321,25 +321,27 @@ class TestParser(BaseTest):
             # Bad continuation byte (restored as ASCII)
             pb(b'"\xe1\x28\xa1"', '"\ufffd(\ufffd"')  # )
 
-            # The following all fail and need to be fixed in the SIMD parser
+            # The following all fail when using SIMD and need to be fixed in the SIMD parser
+            if which != 1:
+                continue
 
             # Overlong 2-byte sequence for U+0000 (should be `0x00`)
-            # pb(b'"\xc0\x80"', '"\ufffd\ufffd"')
+            pb(b'"\xc0\x80"', '"\ufffd\ufffd"')
 
             # Overlong 3-byte sequence for U+0000 (violates boundary)
-            # pb(b'"\xe0\x80\x80"', '"\ufffd\ufffd\ufffd"')
+            pb(b'"\xe0\x80\x80"', '"\ufffd\ufffd\ufffd"')
 
             # Overlong 4-byte sequence for U+0000 (violates boundary)
-            # pb(b'"\xf0\x80\x80\x80"', '"\ufffd\ufffd\ufffd\ufffd"')
+            pb(b'"\xf0\x80\x80\x80"', '"\ufffd\ufffd\ufffd\ufffd"')
 
             # High surrogate code point
-            # pb(b'"\xed\xa0\x80"', '"\ufffd\ufffd\ufffd"')
+            pb(b'"\xed\xa0\x80"', '"\ufffd\ufffd\ufffd"')
 
             # Low surrogate code point
-            # pb(b'"\xed\xb0\x80"', '"\ufffd\ufffd\ufffd"')
+            pb(b'"\xed\xb0\x80"', '"\ufffd\ufffd\ufffd"')
 
             # Too large first codepoint
-            # pb(b'"\xff\x80\x80\x80"', '"\ufffd\ufffd\ufffd\ufffd"')
+            pb(b'"\xff\x80\x80\x80"', '"\ufffd\ufffd\ufffd\ufffd"')
 
 
     def test_find_either_of_two_bytes(self):