content lost when starting 7.9.1 Android WP post, then adding on 4.8.1 server WP

I began a post on my Android smartphone using 7.9.1 level app. I continued the post from where I left off using PC browser on 4.8.1 level server-based version. Later I tried to finish it on smartphone, but the only content there was the original incomplete content. I tried to get out without updating, to no avail. Apparently as I exited it updated the draft online and I lost all the content written from the browser.
(1) Is that a bug or did I do something wrong?
(2) Is there a way to bail out without also updating the draft?