Did you ever get a resolution or root cause?   We had this happen to us today in our message logs.

02/01/22-08:56:16:798 (19248) 1 [Generic.Event] Journal Daemon has been inactive with I/O pending for 10 seconds:

02/01/22-08:56:52:672 (34576) 2 [Utility.Event] ISCLOG: SuperServer Super Server job slave failure ns=%SYS rtn=%SYS.SERVER 
02/01/22-08:56:58:152 (34576) 1 [Utility.Event] SuperServer failed to start slave server