With a Pi4 and Bullseye version of Pi OS (Version 2021-10-30-raspios-bullseye-armhf-full.img) I found that the V1 Ceed display is distorted:
In case its helpful for others, this is what fixed the issue for me:
a) The Pi4 has two HDMI sockets. First ensure the PiTop HDMI connection is plugged into the HDMI socket nearest the USB C connector.
b) Add the following to the /boot/config.txt file:
hdmi_group=2
hdmi_cvt=1366 768 60
hdmi_mode=87
c) Then create or edit /etc/X11/xorg.conf to be as follows:
Section "Monitor"
Identifier "Ceed"
Modeline "Ceed" 70.12 1368 1414 1446 1498 768 772 776 780 +hsync -vsync
Option "PreferredMode" "Ceed"
EndSection
Section "Screen"
Identifier "Ceed"
Device "HDMI-1"
Monitor "Ceed"
EndSection
d) Reboot (sudo reboot) and the display is fixed