Multigroup Date import is invalid

My date field is inside a multigroup and it's getting the "The dates are invalid" message no matter which widget I use.

It's similar to this solved issue: http://drupal.org/node/374346. The only difference is my date field is inside a multigroup. I've already installed the latest dev, but I'm still getting this message. I've also added a date field outside the multigroups with the exact same data/widget/settings for comparison, and the import goes fine. Everything is the same except for the fact that this field is inside the multigroup. Grar!