Found left-over process plymouth on boot

Hi *, because of the recent problems with plymouth I checked my journal for plymouth messages more thoroughly and found: Nov 30 14:29:51 client systemd[1]: plymouth-switch-root.service: Deactivated successfully. Nov 30 14:29:52 client systemd[1]: plymouth-start.service: Found left- over process 463 (plymouthd) in control group while starting unit. Ignoring. Nov 30 14:29:52 client systemd[1]: plymouth-start.service: This usually indicates unclean termination of a previous run, or service implementation deficiencies. Is that an expected behavior? It seems, that the plymouth process from the early boot phase remained running - correct? TIA. Bye. Michael.