What are the restrictions for including links in resource bundle messages?

Summary:

When I include a link in the text within a resource bundle message the digital assistant fails to connect and i just get an error message

Content (required):

We are trying to include some tips in the welcome messages that the DA provides when a user connects but in some circumstances the contents of the message cause the DA to respond that it has been unable to connect to the application. Plain text messages work fine and behaviour is as expected, if we add double quotes (") into the text the DA fails to connect as described above. If we add a link in the text the DA also fails to connect, however, I have added text with a link to the unresolvedIntent bundle message and that works