One or both of two scenarios may occur:
Indicative for this behavior is the following error in the JWP log:
U00003434 Server routine 'TaskListComponent/apitasklist/<client>/<user>/<dep>' required '57' minutes and '20' seconds for processing.
U00003434 Server routine 'TaskListComponent/apitasklist/100/USER001/DEP002' required '57' minutes and '20' seconds for processing.
Update to a fix version listed below or a newer version if available.
Automation Engine v12.2.4 - Available
Automation Engine v12.3.0 - Available