Clicking on link from browser results in null person

Clicking on a link from a browser window results in the spark client opening with the value "null" for the person.

Spark version 2.6.3

This is on a windows machine and affects chrome, firefox and IE.

Link is configured as

xmpp:username@somewhere.com?message

and not

xmpp://username@somewhere.com?message

Is this a problem? Nothing is showing in the logs, anyway to up the logging level?

Thanks!