System version: Fedora 26 Alpha LXQT Linux version 4.11.0-0.rc3.git0.2.fc26.x86_64 Fresh installation, 1 user created. On Login screen (acesed via 'logout' option, not 'lock screen'), same user is listed twice. Both selection are accessible with the same password, no difference spotted. Just listed twice.
https://www.reddit.com/r/Fedora/comments/6cu81w/think_i_made_a_minor_boo_boo_on_install/ I also want to point out that on a live image (NOT INSTALLED), the users and groups already have duplicated entries. This maybe a bigger problem than just duplicated real user accounts after installation...
KDE is having the same problem... https://bugzilla.redhat.com/show_bug.cgi?id=1446782
Upstream fixed it for lxqt-admin, see bug #1459642.
Please mark this as duplicate of bug #1446782 and a bug for sddm instead of lxqt-session A patch is available, see https://bugzilla.redhat.com/show_bug.cgi?id=1446782#c9
*** This bug has been marked as a duplicate of bug 1446782 ***