When the user clicks an action button, the workflow is transitioning to one or more execution steps. The default behavior is for a clocking page to be displayed while the execution is performed. There is a timer that brings up this page when it expires. I do not know if the timer value is configurable. When the timer expires, the following is displayed:
The maximum wait time for this request execution has been exceeded. The request execution in progress will continue to run until it reaches completion or times out. At this time, you may navigate away and try accessing the request at a later time, or reload the request while it is still in progress.
As the message states, only the wait page has ended and the execution step continues to execute. You can use the link labeled reload to reload the current request display page or you can open any other dashboard page. This just keeps you from having to wait for the execution to complete before doing something else.
There is an option on the execution step setup to specify if the wait page or the request page should be displayed when the execution step starts. It is labeled Page Response and has two options:
Finish Execution before displaying the request page to the user
Display the request page immediately while execution is still running
We have always used the first option and see the behavior you are seeing. I have no experience with the second but have always been concerned that it would be confusing to the users.