This inability to easily set umask is not specific to Kubuntu or Dolphin.
It happens since at least 17.04 probably related to use of systemd.
https://bugs.launchpad.net/ubuntu/+source/gnome-session/+bug/1701757 https://bugs.launchpad.net/ubuntu/+source/gnome-terminal/+bug/1685754 https://bugzilla.gnome.org/show_bug.cgi?id=780622
Before 17.04 just setting your favorite umask in /etc/login.defs did the job once and for all.
This inability to easily set umask is not specific to Kubuntu or Dolphin.
It happens since at least 17.04 probably related to use of systemd.
https:/ /bugs.launchpad .net/ubuntu/ +source/ gnome-session/ +bug/1701757 /bugs.launchpad .net/ubuntu/ +source/ gnome-terminal/ +bug/1685754 /bugzilla. gnome.org/ show_bug. cgi?id= 780622
https:/
https:/
Before 17.04 just setting your favorite umask in /etc/login.defs did the job once and for all.