An alternative to this is to force the user to reload

This is precisely what is supposed to happen. The same condition that is used to display the "Saved by merging changes" notification message is used to reload the editor:

// If documents have been merged we need to reload to get latest saved version.
if (response.responseJSON && response.responseJSON.mergedDocument) {
  this.reloadEditor();
}

So the intention is clearly to reload the editor when the save is done by merge. We need to see why the reload doesn't happen in your case. I'll try to reproduce on a clean 14.10.18.