Using dictation in Facebook Messenger on Apple watch

Hi everyone. I've been enjoying using dictation on my new Apple watch (Series 2). However, when I go in to Facebook messenger, dictate the message and then double tap with two fingers to finish the dictation, instead of giving me the interpretation of what I've said, the app simply sends the message. Obviously, this makes the app pretty difficult to use on the watch since often I have to try the dictation once or twice to get it totally accurate. Just wondered if any other messenger users had experienced this issue? Dictation works as it should in all of the other apps.