I am currently working on a fresh multisite WP installation. Have it as a sub-directory based setup:
With your Domain Mapping plugin I am mapping domain1.com/sub1 to domain2.com as follows: Front end redirect should be disabled and entered domain should be used..
All is fine if I access the website via domain2.com (both front end and backend work flawlessly as far as I can see).
However, if I use domain1.com front end is fine but I'm having issues with the backend where permalinks are wrong, pointing to domain1.com without the "/sub1/" bit. That breaks all links to view a particular post, preview post, view category, etc.
The fact that your domain mapping plugin works with a sub-directory based multisite is great (as opposed to the other similar plugin available through WP plugin repository which requires a subdomain based structure) as I really need to stick to using sub-directories on this particular occasion. It's just the little bug in printing correct permalinks in the backend holding me from moving forward.
Does this sound like an easy fix, possibly?
Thanks a lot for the Black Friday deal, a huge saver indeed!