Lightdm as well as sddm are running in some kind of loop after login

Hi @all I have a problem with the display manager which is driving me crazy.
Actually I’m on back on Kernel 5.4.78 and am using lightdm as Display manager.

At least since the last manjaro update I realized that after each reboot and login lightdm is running in some kind of loop approximately for 3-10 Minutes. In case of standby or locked screen, after login it runs much longer in some kind of loop.

The task manager is showing the following entry, running on 25% constantly:

/usr/lib/Xorg :0 -seat seat0 -auth /run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch

So I thought ok maybe lightdm has some problems. Then I switched over to sddm (at that time i was using the 5.9.10-1 Kernel version) and somehow the same happend here, but with sddm running constantly on 25% CPU usage:

/usr/lib/Xorg -nolisten tcp -auth /var/run/sddm/{d9dbcf70-ce4f-4569-80d0-1ad99190798e} -background none -noreset -displayfd 17 -seat seat0 vt1

After that I decided to go back to 5.4 again and switch over to lightdm.
Then I did update-grub because also the boot processed took longer. Normally grub appeared after 2-3 seconds when I switched on the notebook and I was able to navigate within the grub menu to select te bootloader with my external USB keyboard. But since one week or so I have to use the notebook keyboard itself if I want to navigate within the grub menu.

And at least the boot process itself is much longer. Normally it took about 15-20 seconds or so. Now it takes up do 50 seconds. Which is not a problem for me, but seems something has changed but I don’t know what.

I have a Thinkpad X260, with Intel integrated graphics. I use the stable branch of manjaro.