Recently added IN support seems to only work in DS when it is used alone in the queryFilter.
For example: This works correctly and returns a correct response.
However a compound filter will get rejected saying the operator IN is not supported.
"reason": "Bad Request",
"message": "The query request cannot be processed because its query filter '(/fullobject/userName IN "[\\"user0a\\"]" and true)' contained an unrecognized or unsupported filter operator 'IN'"