No idea actually.
Try to add to Section "Device" inside /etc/X11/mhwd.d/nvidia.conf this option:
Option "ConnectToAcpid" "Off"
Make sure you update the system too
sudo pacman-mirrors -f5 && sudo pacman -Syyu
then reboot
Also, could you check if you have installed the gdm-plymouth and eventually replace it with gdm ?