Group not transferred to Mailchimp

Hi,
first of all thank you for the great plugin! I’ve been using magicactionbox on my homepage for a bit now and it has been working great.

Now I wanted to create an opt-in form for my homepage. So I copied an existing one and just changed the title and the origin field (everything else shall be the same, I only want to have a way to track how many people signed up from the homepage).

However, the data that gets transferred to mailchimp does not include the group. The group is chosen in magicactionbox but it’s empty in mailchimp. As my email automation is based on groups, those subscribers get no freebie then.

I also tried to set up a completely new action box with the same settings, but I have the same problem.

Any ideas?

Thank you!