This code produces an error

JHTML::calendar(
 '12-30-2015',
'something',
'something',
 '%m-%d-%Y'
);

This happens only with the date format %m-%d-%Y.
If you change the date format (e.g. %Y-%m-%d) and supply a date relative to that, works fine.

After some debugging i found out:
1. No matter what date is supplied the value becomes 01-01-1970
2. The error is generated by a code in the title of the text input

title="' . ($inputvalue ? static::_('date', $value, null, null) : '') 

file: libraries/cms/html/html.php
function: calendar
joomla version: 3.4.5