SPARQL Query Form in Admin-UI is using wrong server address

In the Admin-UI we have global javascript variables for base-URL/-URI of the installation:

_BASIC_URL which is the base URI for local (RDF-)resources on the server
_SERVER_URL which is the base URL to access the different webservices.

In many (most?) cases these two variables have the same value.

But sometimes not, and SNORQL is using the wrong one (should be _SERVER_URL)