Suggested site id is already taken

[mauritsvanrees]

When I already have some sites and I add a new one, it seems the suggested site id is wrong. I have seen this error several times already the past weeks:

BadRequest: http://localhost:8080/@sites
Traceback (innermost last):
  Module ZPublisher.WSGIPublisher, line 181, in transaction_pubevents
  Module ZPublisher.WSGIPublisher, line 391, in publish_module
  Module ZPublisher.WSGIPublisher, line 285, in publish
  Module ZPublisher.mapply, line 98, in mapply
  Module ZPublisher.WSGIPublisher, line 68, in call_object
  Module plone.rest.service, line 21, in __call__
  Module plone.restapi.services, line 19, in render
  Module plone.distribution.services.sites.add, line 49, in reply
  Module plone.distribution.api.site, line 165, in create
  Module plone.distribution.api.site, line 102, in _create_site
  Module plone.distribution.api.site, line 50, in _create_bare_site
  Module OFS.ObjectManager, line 748, in __setitem__
  Module OFS.ObjectManager, line 335, in _setObject
  Module OFS.ObjectManager, line 126, in checkValidId
zExceptions.BadRequest: The id "Plone3" is invalid - it is already in use.