Uncaught SecurityError: Failed to read the 'contentDocument' property from 'HTMLIFram

@Vinod Dalvi. So, on update to 4.6.1.2, I get this error message.:

Uncaught SecurityError: Failed to read the 'contentDocument' property from 'HTMLIFrameElement': Blocked a frame with origin "http://my.modernnotion.com" from accessing a frame with origin "http://modernnotion.us6.list-manage.com". Protocols, domains, and ports must match.

Some background to the issue: I have created a customized newsletter popover (discussed in this support thread), that has a link to a mailchimp key in it. The error that I am now getting with this update has to do with the frame element and the ports not matching in the frame elements. This wasn't a problem before, but since you guys started using an iframe html element, (in the form_submit function of the new public.min.js file), now it throws the error message. Subsequently, it doesn't open my mailchimp newsletter sign up form in a new tab . I replaced the public.min.js file with the old public.min.js (4.6.1.1) file and it works now. But, I just thought I would let you know of the error. Thanks!