In Campaign Standard, the workflow engine guarantees that a workflow instance is executed by only one process. Blocking activities such as imports, long running queries or writes into the database prevent the execution of any other task when running.
On the other hand, non-blocking activities do not block the execution of other tasks (usually activities waiting for an event such as theScheduleractivity).
This can lead to a scenario where a schedule-based workflow can start executing even when the previous run of that same workflow has not yet finished, potentially leading to unexpected data issues.
Therefore, when designing a scheduled workflow which includes multiple activities, you need to make sure that the workflow is not rescheduled until it is finished. To know how to make sure that a scheduled workflow is not rescheduled until one or more tasks from a previous execution is still pending, check this documentation: Scheduled workflows’ overlapping execution
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