'Record Flush'ACT is an Internal Event. Type Internal events cannot be raised synchronously (Wait=Yes); internal events can ONLY be raised asynchronously (Wait=No).
Events that are raised asynchronously (Wait=No) are never processed immediately; instead, they are added to the event queue where they will be processed in the future and in the same sequence in which they were queued (FIFO).
At runtime in an online task, the runtime engine only checks the event queue during its interactive phase, that is, when the runtime engine is ready to accept user input. In older parlance, the interactive phase is when task execution is within the Record Main.
Thus, events raised asychronously will only be processed during the interactive phase of task execution.