We experience strange things during process creation in the Fusion engine. A process is created but the engine stalls after the First activity becomes ready.
There is however another process present in the engine which has one activity which has no routing to other activity (including last).
What happens when this activity is completed? Can strange things happen?
The activity keeps track of the progress of a search process. This process is divided in a number of activities, after each activity the process is routed to the activity step as well as the activity without any routing.
The client software picks up the activity without the routing and completes it and updates a progress bar on the client GUI.
If the process state and topology is such that the process will be "stuck" after an activity is completed, the engine will abort the process. It is possible to have paths through a process that do not lead to the "Last" activity, but these should run in parallel with an activity path that does. This is an unusual configuration, for most processes should end in a controlled, deterministic way. Junctions are a good way to resynchronise parallel activity paths.
I'm not sure what you mean by "the engine stalls." The engine offers or queues ready activities, and waits for clients to start them. Until a client does this (or a process timer expires), the engine will do nothing to newly created process instance. The console will allow you to examine all current activities, and which (if any) sessions are performing them.