I've got a strange issue right after updating to 3.5.1. My sites on the admin bar are all the same, pointing to the site that is currently in use. For example, if I'm managing the site named "Site 1", all sites on the admin bar will display "Site 1". Here is the screenshot: http://bit.ly/X1EM4d (in the screenshot, I'm using the site named "UXbarn Themes".)
Also, if I go to "Network Admin > Sites > All Sites", every dashboard link for every site are all pointing to the multisite root's dashboard. Some plugins got the strange issue too. For example, I had tried to save the setting of "Under Construction" plugin on one of my site but it always redirected me to the root of multisite after saving (and the setting won't be saved on that site).
The issue never happened before. I just noticed this issue after updating to WP 3.5.1.
Note that the root of multisite is: http://themes.uxbarn.com/wp/
Please advise me the proper solution of how to fix this.