In homedir/.xsession-errors we were continually getting the error message
"/etc/X11/xdm/Xsession: [: too many arguments"
In /etc/X11/xdm/Xsession I found that $XKB_IN_USE was not quoted inside
square brackets (test) in two places. Using double quotes around those
expressions got rid of the error message.
Fixed in Rawhide. Thanks for reporting the error!