SalesforceSource Does Not Honor Destination URL on Login

See eg this thread: https://developer.salesforce.com/forums/?id=906F00000008rtEIAQ

Reproducible by setting server to "test.salesforce.com" instead of (eg) "cs59.salesforce.com". Also, the error doesn't percolate up the stack, but simply results in "No results found".

Documentation should be updated to suggest using the aliases instead of the specific instance.