I am creating it from this group page here:
A drop-down should be there with the at least the group the user clicked "New Group" from. This maybe a bug due to access API in CB 1.8 RC1. CB 1.8 RC2 will resolve those checks (what I am using now) and likely resolve this issue for you as I can't confirm such a bug.
BTW when is it planned for?
Likely won't be an RC3, but stable will release shortly after CB 1.8 stable. Will have to see how RC2 feedback goes.
merges array $list_access having strings in local language and an array coming from function get_groups_below_me() which is in the default language.
You need to translate those groups in Joomla as they're pulled from Joomla and passed through Joomlas JText API. It functions like this all over CB.