In funnel reports we can use the "Visits (report-specific)" metric. As soon as a filter is applied, instead of the amount of Visits, the amount of Instances is shown. Unfortunately the report still uses "Visits" as description.
This is no bug. ClientCare:
"In funnels, the "Visits (Report-Specific)" metric will be Instances, but only if you have defined a filter. In that case, it will be Instances of the defined Filter value. If no filter is specified, "Visits (Report-Specific)" will be Visits."
Conclusion of ClientCare:
"though it is not necessarily intuitive, this function is indeed working as designed".
(emphasis by me)
My idea is, maybe it is old-fashioned, use the correct name of the metric. If the report shows Instances, don't call them Visits.