I think there were *multiple* causes of this kind of bug..
Up to plymouth 0.9.5git20210323-0ubuntu1 it lacked robust shutdown support. That was fixed in 0.9.5git20210406-0ubuntu1 but the new version also introduced bug 1942987.
I think we should track this in bug 1942987 and only worry if it still doesn't work after that is fixed.
I think there were *multiple* causes of this kind of bug..
Up to plymouth 0.9.5git2021032 3-0ubuntu1 it lacked robust shutdown support. That was fixed in 0.9.5git2021040 6-0ubuntu1 but the new version also introduced bug 1942987.
I think we should track this in bug 1942987 and only worry if it still doesn't work after that is fixed.