After we installed Infrastructure Updates we started to experience some problems with InfoPath Forms - getting "There has been an error while loading the form. A required resource could not be downloaded. To try to resume the download, refresh the page.", when using some of the alternative URLs.
SharePoint logs was showing me "WARNING: Invalid Canary for view file"
Based on the info from the Microsoft, there is an known problem with the Alternate Access Mapping in Infrastructure Updates. The next cumulative update is supposed to fix this issue. Will update this post as soon as I get it installed and verified.
Update: After installing SP2 issue was fixed.