stemming behavior for diacritics causes incorrect results

> db.test.insertMany([ { "_id" : 1 , "name" : "iphone" }, { "_id" : 2 , "name" : "iphône" }, { "_id" : 3 , "name" : "iphonë" }, { "_id" : 4 , "name" : "iphônë" } ])     > db.test.ensureIndex({name: "text" })   > db.test.find({$text: {$search: "iphone" }}) { "_id" : 1 , "name" : "iphone" } { "_id" : 2 , "name" : "iphône" }   > db.test.find({name: "iphone" }).collation({locale: "en" , strength: 1 }) { "_id" : 1 , "name" : "iphone" } { "_id" : 2 , "name" : "iphône" } { "_id" : 3 , "name" : "iphonë" } { "_id" : 4 , "name" : "iphônë" }