[Plugin: WordPress MU Domain Mapping] Endless loop after remote login

Here’s the setup:
Subdirectory multisite installation (3.4.1) for which the primary domain is a subdomain (staging.mydomain.com). Additional sites have other subdomains mapped to them, so staging.mydomain.com/othersite = othersite.mydomain.com. The “More Privacy Options” plugin is being used to restrict access to the additional sites to only logged-in users. The Remote Login option is turned on so every user will be sent to staging.mydomain.com to log in before redirecting to the site they are attempting to access.

Here’s the problem:
With Remote Login turned on, a user attempting to access othersite.mydomain.com gets sent to staging.mydomain.com/wp-login.php. After logging in, the form attempts to send them to othersite.mydomain.com/wp-login.php?redirect_to=%2F. An endless loop starts where the browser alternates connections between staging.mydomain.com and othersite.mydomain.com while the page sits blank.

– This doesn’t happen with Remote Login turned off, but in this case, we want it turned on so that all logins go through the same domain.
– Deleting cookies doesn’t fix the problem.

I’m at a loss for what to try next, so troubleshooting suggestions are appreciated.

http://ww.wp.xz.cn/extend/plugins/wordpress-mu-domain-mapping/