I just discovered something odd that explains why umask isn't
getting set for the user (me).
Traditionally (I researched countless sites about the proper
place for things and, as I said, it has always worked in the
past, right up until F26), umask is supposed to be in
bash_profile.
However, I just noticed that my setting gets unset in
/etc/bashrc, because in Fedora 26, umask is set in the system
bashrc in /etc, thus unsetting my setting.
I haven't looked at the value of the PATH variable, but I
believe it is okay (I just append $HOME/.local/bin) and this
appears to occur in both virtual terminals and graphical. As
well, my aliases and functions work, so, what it all boils
down to, as far as KDE is concerned, anyway, is that...
*umask must be set in .bashrc, not in .bash_profile*