Used 229-4ubuntu19, added set +x at the top of the init-top/udev script and booted with break=bottom to clearly observe initramfs boot messages and check that there is only one (devices) trigger.
Upgraded to 229-4ubuntu20, added set +x at the top of the init-top/udev script booted again and clearly boserved that subsystems and devices are triggered.
Used 229-4ubuntu19, added set +x at the top of the init-top/udev script and booted with break=bottom to clearly observe initramfs boot messages and check that there is only one (devices) trigger.
Upgraded to 229-4ubuntu20, added set +x at the top of the init-top/udev script booted again and clearly boserved that subsystems and devices are triggered.