If a contact is noted to have joined the workflow too late for a step, this is a sign that the workflow is experiencing what we refer to as throttling.
Let's say you have 34,000 contacts enrolled in a workflow. Your workflow tool processes 20 contacts per second, therefore 1,200 contacts will execute an action per minute. All in all, it will take about 28 minutes for all 34,000 contacts to execute one action.
Keeping that in mind, let's assume a couple of things:
- All contacts were enrolled today at 3:40 PM.
- The workflow in question is a date-based workflow and the first action is scheduled to execute today at 3:45 PM.
In this case, there will be contacts in this workflow for whom you will see the Contact joined workflow too late for this step message because even though they joined the workflow, it took them well over five minutes to execute on the action.
Your workflow may experience throttling if there is a mass enrollment of contacts and the window of execution is too small for contacts to effectively be enrolled and execute on the action in question.