When I ask 18.104.22.168 a question over UDP or TCP, I get no EDNS Padding. This is correct behaviour.
When I ask 22.214.171.124 a question over TLS, I get EDNS Padding as long as my query has an EDNS OPT Additional. This is correct behaviour.
Over DoH (to https://dns.Cloudflare.com/dns-query, with Content-Type and Accept set to application/dns-message), I get EDNS padding, even if my query does not have an EDNS OPT Additional. This appears to be a bug.
Please do not pad responses if the client has not indicated EDNS support.