Thomas Döring I'm using 2.0 and this is not an issue for me anymore. It actually wasnt the plugin's fault but a misconfiguration of the nginx proxy ssl certs.
I put an nginx proxy infront of Jenkins to handle the ssl stuff. When adding the cert you must concatenate the server certificate and the CA certificate together. For example:
cat servercert.crt ca_cert.crt > nginxcert.crt
If you dont do this and only use servercert.crt, everything will look fine if you use a browser to go to Jenkins but when you use a tool like curl, the cert will not be trusted. I've seen other system tools behave this way and have also seen this when using SSL libraries for some programming/scripting languages which is probably why GitHub's markdown renderer didnt want to load the badge. After configuring this properly, the badge loaded with no problems.
Thanks.
Kevin Carrasco Thank you for your feedback. I think I can mark this issue as closed then.