Discourse version 2.8.0.beta10
Tapping and dragging a text selection (1 action), then choosing the
quote button, will populate the quote to a reply
But tapping then dragging (2 actions, then choosing the
quote button will result in no action (reply with a quote will not populate)
This does not appear to be an issue if accessing the forum from Safari in iOS.
Please let me know if you need any more info. Thanks!