I think that if there is a genuine circular dependency then the services won't start ever. But I think it is possible to introduce services that assume other services are up and have an apparent dependency circularity. The trick is to have all your services resilient to it's start requirements not being met - basically the service has to back off and wait if information it needs isn't yet in the environment... and then ask again - so that when other services are up everything syncs and comes up.
That's fine, until the environment doesn't come up because a hundred services all queried the source of truth simultaneously and caused load that prevented any service from getting its config
