The 3 examples shown in this section of the docs (Connect from MySQL with Authentication) use the following format for the user parameter:

'--user=reportsUser?source=admin'

It looks like that initial quote is in the wrong place. Instead the parameter should be specified as follows:

--user='reportsUser?source=admin'

i.e. the quotes should only wrap the parameter value itself.

Also, the following section (Connect from MySQL with Authentication and TLS/SSL) specifies the user using a '-u' parameter. For consistency perhaps we should use just one format, either '-u' or '--user', rather than a mixture of the two. (Note: the '-u' parameter does not use an equals '=', while the '--user' variant does. See the MySQL docs for details)