ADDITIONAL SYSTEM INFORMATION :
Windows 10, OpenJdk 20

A DESCRIPTION OF THE PROBLEM :
When using the English(Canada) regional format on Windows, while extracting the date pattern by using the code below, the pattern is outputted as: M/d/yy.

With previous versions of Java, Java 11 for example, the pattern output is: y-MM-dd.

Code used to recreate:

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :

DateFormat defaultDateTimeFormat = (DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.MEDIUM));
SimpleDateFormat sdFormatter = (SimpleDateFormat) defaultDateTimeFormat;
String pattern = sdFormatter.toPattern();

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Pattern should be equal to y-MM-dd for Canada.
ACTUAL -
M/d/yy

FREQUENCY : always