I did some research into what was going on within the FormHelper.php file and here is a breakdown:
In the dateTime() function it checks if $attributes['value'] is empty. If it is it fills that information using $this->value($attributes,$fieldName); populating it with 2013
2013 is then parsed by _GetDateTimeValue()
Within _GetDateTimeValue() it is parsed as numeric, and is translated from unix time; an hour and a half into 1970.
That then is set as the value of the final select box, which has to expand from the minYear to properly accommodate.
For whatever reason Cake does not take into account the explicitely stated dateFormat=>'Y' when is parses with _GetDateTimeValue().
The solution is to insert: $selected => strtotime('now')
which will in the end get properly parsed.
You can also explicitly set $selected to values outside of the range of dates, which I'm not sure would be a wanted before or not.