Post bug reports here: http://open.silverstripe.com.
NOTES: Translatable Issues will be looked at as soon as possible. It looks like translatable and the custom rules are 2 areas we need to tidy up but this release is just to make sure everyones using the same base as we have fixed a few common issues people were coming across.
Your contact us page looks like a standard page type and not a 'User Defined Form' page type. If you cannot see this form field in the create page dropdown then its likely it has not been installed properly