i was now able to reproduce the failure and i think it is indeed a "bitnami failure".
I installed the following instance https://google.bitnami.com/vms/new?image_id=6dyp1SE
to reproduce the error message, install the ssl certificate and nothing more. than try to edit a site with the default editor (with chrome), it should now say that you are offline.
What I think the problem is: in the main menu -> settings -> general WordPress Address (URL) & Site Address (URL) does not adjust automatically from http to http**s**.
The solution was to follow this guide and set the site url and the wordpress url manually to https://mysite.com/
If you want a suggestion for improvement: you could adjust the bitnami stacks in the way, that the WordPress Address (URL) & Site Address (URL) adjusts automatically with installing the ssl certificate. that could possibly implemented in the generate-certificate.sh script, when creating the let's encrypt certificate.
insert this information in the bitnami banner.