also in testing keyboard numlock isn't switched on at session login anymore.
for now, as a workaround, I have installed numlockx
-- Saluti, Luca Pedrielli
Another trick that worked on 2 machines here is to set the numlock on in /etc/sddm.conf.
My general section of sddm.conf looks like this now:
[General]
HaltCommand=
RebootCommand=
Numlock=on
Hope this helps.