We have multiple slave nodes, on windows, all having the number of executors set to 1.

Our workflow is as follows:
Job 1 requests an executor with a specific label and calls Job 2 (waiting for it's completion)
Job 2 requests another executor with same label and calls Job 3 (waiting for it's completion).

Very seldom, we have runs where the same node (with the number of executors set to 1) gets assigned 2 times (we always assign 2 executors to a run).