indexFilterSet is always False with verbosity of "executionStats" or above

For example: db.test.createIndex({a: 1 ,b: 1 ,c: 1 ,d: 1 , g: 1 },{name: "g1" }) db.test.createIndex({a: 1 ,b: 1 ,c: 1 ,d: 1 , e: 1 },{name: "e1" }) db.test.createIndex({a: 1 ,b: 1 ,c: 1 ,d: 1 , f: 1 },{name: "f1" }) Create an index filter for one of the indexes: db.runCommand( { planCacheSetFilter: "test" , query: {a: 1 ,b: 1 ,c: 1 ,d: 1 }, indexes:[{a: 1 ,b: 1 ,c: 1 ,d: 1 , f: 1 }] }) Run the following query: db.test.explain( "executionStats" ).find({a: 1 ,b: 1 ,c: 1 ,d: 1 }) The index is used but indexFilterSet is false in the explain() output Clear the index filter: db.runCommand( { planCacheListFilters: "test" } ) Create a filter for a different index: db.runCommand( { planCacheSetFilter: "test" , query: {a: 1 ,b: 1 ,c: 1 ,d: 1 }, indexes:[{a: 1 ,b: 1 ,c: 1 ,d: 1 , g: 1 }] }) Now re-run the query. The index is used, but indexFilterSet is false