You delegated the subdomain pbe.mouk.dev to our nameservers, and our nameservers direct your domain name directly onto our servers. This means this subdomain is not being passed through Cloudflare, and is not using their SSL system. So any SSL settings you do in Cloudflare have no effect on your domain name right now.
This means your domain name is affected by the issues described here:
Since you’re already using Cloudflare, I would recommend to find the DNS record to use for your account, and add it to Cloudflare’s DNS, and remove our nameservers there. That way, you can enable Cloudflare on your subdomain and use their SSL.