only can be happen with non-free “multipledomain certificate” …
if you want use a free one…
hmmmm
try cloudflare
domain A.tld create at CF then set IN A etc
then create another add site called DomainB.tld
set under proxy
at cyberpanel u only need to give same path of public_html
or some modification for advance user
because add domain with same path is not alias actualy… only domain forwarder if you use wordpress or similar cms. the BASE_URL will be back to the default one
except you already find out how to do that