Solution
This occurs if event handles are not being closed with each loop iteration. In the
VISA documentation it mentions that a Wait On Event call returns a viHandle specifying the unique occurrence of an event. This event handle must be closed each time you call a VISA Wait on event after you catch your event. In LabVIEW, this is accomplished by wiring the event resource of the Wait On Event VI to a VISA Close VI in your loop. See the example below: