For me, when I clear the text message on my watch, it clears it on my iPhone. I didn't set it up any special way, it just did that from the start.
^^^^^What he said; same here, a feature that is quite handy. Did nothing, the watch just did it. I have an iPhone 6S+, if that matters.
I have an Iphone 6 plus. Which button sequence did you press on the watch itself? My phone still shows the text after reading it on my watch and clearing it. I use forward button to read the text and back button to clear it out.
Shouldnt make a difference as we all have the same OS versions. Mine is 10.3.1. Wonder if there is a setting on the app or phone for this?
I push the down button (lower left side) to clear the message.