The recently released RC2 build of ASP.NET MVC 3 is reported of having a metadata caching bug that manifests itself in at least two scenarios:
Both of above issues are caused by an over-eager caching optimization introduced late in the RC2 milestone. This issue will be fixed in the final ASP.NET MVC 3 release.
You can fix the issues in RC2 by adding one line of code to the Application_Start() event handler within the Global.asax class of your app. You don't need to change any other code within your app. Once you make this change the issues are fixed. You won't need to have this line of code within your app in the final release.