disabling wpautop in TinyMCE settings leads to strange behavior in Text editor

[leedo]

If I disable the wpautop behavior in TinyMCE with a tiny_mce_before_init filter like so:

function ars_disable_tinymce_wpautop($in) {
  $in['wpautop'] = false;
  $in['remove_linebreaks'] = false;
  $in['apply_source_formatting'] = true;
  return $in;

The text view of the editor exhibits some odd behavior when saving. Instead of submitting the current state of the text editor, the text editor is updated with the contents of the HTML view, and then saved.

However, if I click over to the Visual editor before saving it will save correctly. I believe this logic in the wordpress TinyMCE plugin may be the cause:

ed.onSaveContent.add(function(ed, o) {
  if ( ed.getParam('wpautop', true) && typeof(switchEditors) == 'object' ) {
    if ( ed.isHidden() )
      o.content = o.element.value;
    else
      o.content = switchEditors.pre_wpautop(o.content);
  }
});

[leedo]

copy Text editor contents even if wpautop is disabled

[azaozz]

This is pretty much a duplicate of #23743 that we failed to find at the time, fixed in [23745].