Substitution Rules ignore https

Just came across this little irritating bug.

If you create substitution rules, and SSL (https) is enabled on the server, then any Substitution rules specifically accessing just the https port will fail.

e.g. Create Substitution rule

//source.nsf/

//replace.nsf/

Then using the URL

http://myserver/web/source.nsf

http://myserver/web/replace.nsf

(as expected)

However using HTTPS

https://myserver/web/source.nsf

https://myserver/web/source.nsf

With no substitution.

Anyone else get this bug/feature? Running R6.5.1 on Linux, quad cpu and plenty of ram.