Hi @cdiazorases, thanks for downloading the plugin and for the open topic. I am Andrea and I will help you with your request.As a prinpal tool recommended and that I use often is https://securityheaders.com (running a test I see an A+ grade), regarding your issue found with https://observatory.mozilla.org this depends on how the tool is designed (example: mozzilla seems not to see the headers if they are duplicated) this doesn’t mean that your site doesn’t use the headers because running a test with securityheaders.com, https://domsignal.com/ and https://snyk.io (all these tools very popular or known evaluating your A+ headers).
Also, I would like to tell you that in the next few hours I will be releasing version 5.26 which will implement the ability to customize CSPs to make your protection even more comprehensive.
I hope I have answered your question in the shortest time and please do not hesitate to contact me.
