diff --git a/poi/src/main/java/org/apache/poi/ss/usermodel/DateUtil.java b/poi/src/main/java/org/apache/poi/ss/usermodel/DateUtil.java
index 01d825ac74..1b23d8dcce 100644
--- a/poi/src/main/java/org/apache/poi/ss/usermodel/DateUtil.java
+++ b/poi/src/main/java/org/apache/poi/ss/usermodel/DateUtil.java
@@ -78,10 +78,10 @@ public class DateUtil {
     private static final Pattern date_ptrn5 = Pattern.compile("^\\[DBNum([123])]");
 
     private static final DateTimeFormatter dateTimeFormats = new DateTimeFormatterBuilder()
-            .appendPattern("[dd MMM[ yyyy]][[ ]h:m[:s] a][[ ]H:m[:s]]")
-            .appendPattern("[[yyyy ]dd-MMM[-yyyy]][[ ]h:m[:s] a][[ ]H:m[:s]]")
-            .appendPattern("[M/dd[/yyyy]][[ ]h:m[:s] a][[ ]H:m[:s]]")
-            .appendPattern("[[yyyy/]M/dd][[ ]h:m[:s] a][[ ]H:m[:s]]")
+            .appendPattern("[dd MMM[ yyyy]][[ ]h:m[:s][.SSS] a][[ ]H:m[:s][.SSS]]")
+            .appendPattern("[[yyyy ]dd-MMM[-yyyy]][[ ]h:m[:s][.SSS] a][[ ]H:m[:s][.SSS]]")
+            .appendPattern("[M/dd[/yyyy]][[ ]h:m[:s][.SSS] a][[ ]H:m[:s][.SSS]]")
+            .appendPattern("[[yyyy/]M/dd][[ ]h:m[:s][.SSS] a][[ ]H:m[:s][.SSS]]")
             .parseDefaulting(ChronoField.YEAR_OF_ERA, LocaleUtil.getLocaleCalendar().get(Calendar.YEAR))
             .toFormatter();
 
diff --git a/poi/src/test/java/org/apache/poi/ss/formula/functions/TestTimeValue.java b/poi/src/test/java/org/apache/poi/ss/formula/functions/TestTimeValue.java
index 1cbee788b8..b7f4d4a6ab 100644
--- a/poi/src/test/java/org/apache/poi/ss/formula/functions/TestTimeValue.java
+++ b/poi/src/test/java/org/apache/poi/ss/formula/functions/TestTimeValue.java
@@ -63,6 +63,9 @@ final class TestTimeValue {
             confirmTimeValue(new StringEval("12:00"), 0.5); // Serial number of a time entered as text.
             confirmTimeValue(new StringEval("6:00 PM"), 0.75); // Serial number of a time entered as text.
             confirmTimeValue(new StringEval("12:03:45"), 0.5026041666642413); // Serial number of a time entered as text.
+
+            // this is not yet right as the milliseconds are not counted - but this used to cause a parse issue before
+            confirmTimeValue(new StringEval("12:03:45.386"), 0.5026041666642413);
         } finally {
             LocaleUtil.setUserLocale(null);
         }