Links to rest service endpoints do not work in the channel manager

The problem can be reproduced in the gogreen demo:

• open the US website channel
• use the link to "API" in the footer menu
• choose Rest Browser from the left menu
• click "Execute Rest Call"

In the site this works, you get to see output. In the channel manager (in a local build), there is a 404 on this request:

http://localhost:8080/site/_cmsinternal/restapi/topproducts?org.hippoecm.hst.container.render_host=localhost?_type=json&sortby=hippogogreen:rating&sortdir=descending&max=10

The logs show:

[INFO] [talledLocalContainer] 14.11.2017 14:26:17 WARN  http-nio-8080-exec-9 [JAXRSInInterceptor.processRequest:166] No root resource matching request path /site/restapi/ has been found, Relative Path: /. Please enable FINE/TRACE log level for more details.
[INFO] [talledLocalContainer] 14.11.2017 14:26:17 WARN  http-nio-8080-exec-9 [WebApplicationExceptionMapper.toResponse:72] javax.ws.rs.NotFoundException: HTTP 404 Not Found
[INFO] [talledLocalContainer]     at org.apache.cxf.jaxrs.utils.SpecExceptions.toNotFoundException(SpecExceptions.java:89)
[INFO] [talledLocalContainer]     at org.apache.cxf.jaxrs.utils.ExceptionUtils.toNotFoundException(ExceptionUtils.java:129)

Try it outside the channel manager, and you get the same logging and problem. Removing /_cmsinternal gets you a better response, but check the request parameters: there are two ? in it due to the insertion of ?org.hippoecm.hst.container.render_host=localhost