June 2013 CU => uncaught sys.InvalidOperationException: "timeZoneId"

Hey,

after successful SharePoint CU Update (June 2013) we experiencing a script error in enterprise search center: the webparts (SearchNavigation, ResultScriptWebPart, ...) on the page are just not loading.

In IE-Dev-Console (F12) we found a script error:

SCRIPT5022: Sys.InvalidOperationException: "timeZoneId" ist keine Eigenschaft und kein vorhandenes Feld. 
ScriptResource.axd?d=7dQ5Nvaem_(...)

- "ist keine Eigenschaft und kein vorhandenes Feld." = is not a property or existing field

$web.RegionalSettings.TimeZone.ID is 4

I have no idea what happened during update :/

Any idea?

/Valerian