I'd like to state that unfortunately sometimes it is simply that we forget to deselect/delete the whole quoted text from the bottom and this why almost in my case both the selected quoted text and the full text appear - depending on the client.
Talking about email clients I want to spread the voice (one more time farther then Tom, the owner of Misc) about my actual choice for Android: FairEmail https://email.faircode.eu absolutely recommended! No relationship with it but honestly happppy and endorsing it. :D -- Daniele Bonini