The issue is that the Running task count is not reflective of the reality.
Tasks are shown to have a status of running, when there are actually no running tasks.
The issue is a cosmetic one and is not expected to adversely impact the environment it is observed in.
The issue can be observed in the SDDC Manager UI by opening the Tasks list at the bottom of the UI and clicking the Filter button next to Task Status.
An example is shown below:
VMware Cloud Foundation 5.x
The running task count appears to increment when a task is running, but then not decrement after the task completes.
The SDDC Manager UI is setting the number of running tasks to the total number of tasks.
There is no workaround available.
The issue will be resolved in a future release.