Gitlab Monolith Container Certificate contains the same serial number as another certificate

I’m running 12.7.2-ce.0 in docker 1.13.1 in a Centos 7.7 Virtualbox VM.
When connecting with latest Firefox I get an error:

An error occurred during a connection to vagrant-gitlab:8443. You are attempting to import a cert with the same issuer/serial as an existing cert, but that is not the same cert. I did not store any exeption in Firefox, nor will it let me add one for this local URL.


The help page has no answer I can use.

Is this a known problem, and has it been fixed?