The configuration parameter "xwiki.url.protocol" in "xwiki.cfg" is not always taken into account

Steps to reproduce

• XWiki standard Jetty + HSQLDB zip package version 11.3
• In "xwiki.cfg", configure "xwiki.url.protocol" to "https"
• Copy the code below in a page and head to that page over http:

$doc.getExternalURL()
$xwiki.XWiki.Param("xwiki.url.protocol") 

Expected behaviour

• The output URL contains the https scheme

Actual behaviour

• The output scheme is http, while the configuration parameter is correctly output to "https"

NB: the bug is not present in XWiki 10.2