InOperatorQueryFilterTransformer was not integrated into the filter evaluations for DelegatedAdminFilter.
The "IN" filter does not work for delegated admin filters. The filter needs to be transformed first into a set of OR using the InOperatorQueryFilterTransformer and the delegated admin source did not integrate this before evaluation.
Write a longer filter with a group of OR eq filters skipping the convenience of using the "IN". such as:
This may not be a feasible work around where an array is building dynamically and implementers will not know the exact values. Such as with a dynamic filter of