Google gets a wrong url for the stylesheet (/jawr-css/gzip_null.@en/bundles/dmlights.css), this influences both the cached google pages and the page preview when searching.
From a quick debugging session, it seems that the root cause lies in the BrowserResolver. When the browser is not in the list, it returns null. This results in the browser not being added to the variant map.
When that happens, the variant key in JoinableResourceBundleImpl.getURLPrefix(variants) isn't found in the prefixMap resulting in the url above.
An example of a correct url is: /jawr-css/gzip_1209578149.@@nl/bundles/dmlights.css