nemozone

Well, it appears that on systems where the hosts conf has been borked. Or that Firefox on rare occasions has a bug which has redirection issues, whatever...

Here are some links which refer to this very odd behavior

https://support.mozilla.org/bm/questions/1011327

https://support.mozilla.org/de/questions/1326837

https://bugzilla.mozilla.org/show_bug.cgi?id=1453207

Well one could apply the mentioned solutions or edit the hosts conf file

sudo cp /etc/hosts /etc/hosts.bak
sudo vim /etc/hosts 

#Remove all entries or comment them out, whatever
#On a test system, have these fresh entries
127.0.0.1        localhost
127.0.1.1        test

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters 

Don't forget to save your changes and done