diff --git a/src/pcre2_convert.c b/src/pcre2_convert.c
index 8a2b293d5..8a525f50c 100644
--- a/src/pcre2_convert.c
+++ b/src/pcre2_convert.c
@@ -679,9 +679,10 @@ if (*pattern == CHAR_EXCLAMATION_MARK
       len++;
       }
     out->out_str[len] = (uint8_t) separator;
+    len++;
     }
 
-  convert_glob_write_str(out, len + 1);
+  convert_glob_write_str(out, len);
   }
 else
   convert_glob_write(out, CHAR_LEFT_SQUARE_BRACKET);
diff --git a/testdata/testinput24 b/testdata/testinput24
index 03cecf9b2..c024ebaa4 100644
--- a/testdata/testinput24
+++ b/testdata/testinput24
@@ -330,6 +330,12 @@
 
 /??a??/
 
+/[!a]/
+
+/[^xy]/
+
+/a*[!b]/
+
 #pattern convert=unset
 #pattern convert=glob,convert_glob_escape=0
 
diff --git a/testdata/testoutput24 b/testdata/testoutput24
index feac50249..1daf6cfb9 100644
--- a/testdata/testoutput24
+++ b/testdata/testoutput24
@@ -512,6 +512,15 @@ No match
 /??a??/
 (?s)\A..a..\z
 
+/[!a]/
+(?s)\A[^a]\z
+
+/[^xy]/
+(?s)\A[^xy]\z
+
+/a*[!b]/
+(?s)\Aa(*COMMIT).*?[^b]\z
+
 #pattern convert=unset
 #pattern convert=glob,convert_glob_escape=0