dmraid / LVM boot problems after upgrading to Ubuntu 18.04

I have a problem with dmraid / LVM after upgrading an Ubuntu 16.04 machine to 18.04. The root file system of this computer is located on an LVM-LV on a RAID 1, which consists of two hard disks realized with dmraid.

The start process is stored in an initramfs BusyBox shell after the upgrade. After doing some research, I found that the RAID 1 set was not activated during the startup process. As a result, LVM sees two different hard drives with the same LVM PV ID. LVM refuses to activate the PV while displaying it on multiple devices. As a result, the root file system that is on an LV on the inactive PV is missing.

I was able to boot the system by manually activating the RAID 1 set and instructing LVM to ignore the individual hard drives:

dmraid -ay
lvm vgchange -ay --config 'devices { filter = [ "r|/dev/sd.*|" ] }'
exit

However, this is only a workaround and I want to find a suitable solution to these problems.