Since 2.4.4 the query parameter does not get updated when refreshing the route.
See this twiddle: https://ember-twiddle.com/48d144fbb71cb96220e42dbd664eaef3 (works in 2.4.3 but not in 2.4.4)
I think this is because of #13202, after the second click the content of queryParams is {foo: "2", application:foo: 3} here. Subsequent changes on the QP increment application:foo but not foo.