Coupon sending twice if user subscribes at checkout too

Hi

Great plugin ..
Here’s the deal – iv’e got a modal window for subscription what people use and then on the checkoutpage there’s a checkbox to “subscribe to newsletter” .. so.. when users subscribe to (mailchimp) in the modal window buy something and check the checkbox they subscribe twice (what mailchimp filters out) but .. youre plugin sends a coupon code twice.
I wonder that no one else seemse to have that issue. I dont want to remove the checkbox at the checkout.

Plugin is deactivated right now on the page!

Any ideas?
thanks

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