Steps to reproduce:

• Change your date picker formats to:

  jira.date.picker.java.format	MMM d, yyyy
  jira.date.picker.javascript.format	%b %e, %Y

• Go to the project versions page and add a version with a release date:

• When you try and release this version the release date is pre-populated with an invalid value (wrong format).

Since this column is a date picker we need to use the date picker format that is configured (both in the versions table and in the release version dialog).