I am running the domain mapping plug-in and I have an SSL certificate on the root domain of the network. I have several other sites on the network, for which I don't have an SSL certificate. But I force all logins over the secure domain and the domain mapping plug-in is set to “original domain” under the network settings. Under this configuration previewing a post generates a 404 error. If I change the domain mapping plug-in to use “mapped domain” or "domain entered by the user" and edit the post using the map domain then previewing posts works.
While I would prefer to use the map domain or domain entered by the user setting, WordPress introduced SSL bug with 3.3 that causes all uploads using the mapped domain to use HTTPS:// in the image link, which then results in images not loading because there is no certificate for that particular mapped domain.
This seems like a bug to me in the way the domain mapping plug-in is handling the preview. Has anyone else reported this? Do you think this is something that can be fixed? Are there any workarounds that anyone is aware of to ensure that uploads don't get SSL links? If I could solve that problem I could set the domain mapping plug-in to one of the other options which would then fix the preview issue. I'm hoping that someone can come up with either a fix or workaround.