Cannot Edit Media with Mapped Domains

I am using Domain Mapping, and just noticed the edit media link is broken. The source of the frame pulls from

originalsubdomain.maindomain.tld/etc/etc/etc

So it errors.

If have dashboard use
originalsub.maindomain.tld instead of mappedomain.tld; it works fine.

It also lets me upload, it is just the EDIT media function messing up.

Suggestions?