Description of problem:
logged in as root, no other user account created, Mate user manager starts and says 0 users, fails immediately after.

Version-Release number of selected component:
mate-user-admin-1.6.0-3.fc36

Additional info:
reporter:       libreport-2.17.1
backtrace_rating: 4
cgroup:         0::/user.slice/user-0.slice/user/app.slice/app-glib-mate\x2duser\x2dadmin-5286.scope
cmdline:        mate-user-admin
crash_function: user_list_row_get_user
executable:     /usr/bin/mate-user-admin
journald_cursor: s=498735d462e346e5be4c51e55b25e8ee;i=26a04;b=29718d4881a04506ad48a98423cbc0f4;m=558b5ae5;t=5e3db1195d9b5;x=5a338450497191ee
kernel:         5.18.11-200.fc36.x86_64
rootdir:        /
runlevel:       N 5
type:           CCpp
uid:            0

Truncated backtrace:
Thread no. 1 (10 frames)
 #0 user_list_row_get_user at ../src/user-list.c:173
 #1 user_window_set_list_data at ../src/user-window.c:412
 #2 user_window_new at ../src/user-window.c:438
 #3 users_loaded at ../src/main.c:110
 #5 signal_emit_unlocked_R.isra.0 at ../gobject/gsignal.c:3743
 #9 g_object_notify_by_spec_internal at ../gobject/gobject.c:1341
 #11 set_is_loaded at ../src/libaccountsservice/act-user-manager.c:1589
 #12 load_seat_incrementally at ../src/libaccountsservice/act-user-manager.c:2703
 #16 g_main_context_iterate.constprop.0 at ../glib/gmain.c:4211
 #18 gtk_main at ../gtk/gtkmain.c:1329