Summary

Date picker custom field with the format "dd/MMM/yy", and setting a date before 1950, automatically change the year to 20XX.

Steps to Reproduce

1. Create a date picker custom field
2. Associate the custom field with the project
3. Create a new issue
4. Set any date < 01/Jan/1950

Note that the date was changed to 01/Jan/50 (01/01/2050).

Expected Results

Keep the correct date which was set.

Actual Results

It automatically set the wrong year. 

Workarounds

Under Settings > General Configuration > Advanced Settings, change the date format to dd/MM/yyyy.