I am a speech therapist but my child development is a bit rusty. My 3;10 year old has: intermittent backing; on clusters eg. /fr/ she goes to /sw/; /th/ to /g/; /j/ to /g/. Sorry I don't have time to hunt for the phonetic symbols but that should make sense.
My main issue is the backing. I know by this age it should be resolved. I've made some gentle efforts to work on it but perhaps should be trying harder. I'm wondering whether I should be referring her now?