diff --git a/src/main/java/com/ethlo/time/internal/fixed/ITUParser.java b/src/main/java/com/ethlo/time/internal/fixed/ITUParser.java
index ab7dae9..e414173 100644
--- a/src/main/java/com/ethlo/time/internal/fixed/ITUParser.java
+++ b/src/main/java/com/ethlo/time/internal/fixed/ITUParser.java
@@ -149,7 +149,7 @@ private static TimezoneOffset parseTimezone(int offset, final ParseConfig parseC
             }
         }
 
-        assertNoMoreChars(offset, parseConfig, chars, idx + 6);
+        assertNoMoreChars(offset, parseConfig, chars, idx + 5);
         return TimezoneOffset.ofHoursMinutes(hours, minutes);
     }
 
diff --git a/src/test/resources/test-data.json b/src/test/resources/test-data.json
index 26da8c5..45c64c9 100644
--- a/src/test/resources/test-data.json
+++ b/src/test/resources/test-data.json
@@ -283,7 +283,8 @@
     },
     {
         "input": "2020-12-31T00:00:00-05:00 x",
-        "error": "Trailing junk data after position 27: 2020-12-31T00:00:00-05:00 x",
+        "error": "Trailing junk data after position 26: 2020-12-31T00:00:00-05:00 x",
+        "error_index": 25,
         "lenient": true
     },
     {
@@ -331,5 +332,10 @@
         "input": "4444-04-23t44:44:60",
         "error": "Invalid value for SecondOfMinute (valid values 0 - 59): 60",
         "lenient": true
+    },
+    {
+        "input": "1963-06-19T08:30:06.28123+01:00Z",
+        "error": "Trailing junk data after position 32: 1963-06-19T08:30:06.28123+01:00Z",
+        "error_index": 31
     }
 ]