One of the modes for wbgetentities and wbsetsitelink is to report the sitelinks urls (http://www.wikidata.org/w/api.php?action=wbgetentities&ids=q42&props=sitelinks/urls). This mode will now return empty strings. This did work some days ago so something has changed that creates this failure. It is also visible in current master.
Version: unspecified
Severity: normal