There are a few things here … The main one being that once you have verified and authorized control of a domain then the ACME server remembers this for a period of time ( currently 60 days, but will reduce to 7 days probably at some point. Since you are already authorized (using that account key) then it can issue a certificate without needing to verify again.
There are a couple of options here for you in testing. 1) you can deactivate ( see Authorization deactivation ) or 2) you can simply change the account key you use for the staging server, then you won’t already be authorized, and it will go through the full process.
Personally, I deactivate the authorization every time after successfully getting certificate, since (to me ) that more closely represents the reality of what will happen in reality. I’ll be using the same key, which won’t already be authorized )
On a separate issue, I’m not sure if the “renew” will work - as it will try and renew by the method you used first time - i.e. standalone mode, which is not what you want. I think the above (remembering the authorization ) is the main issue you are hitting first though