Sometimes phantoms exist in drawings. In particular when you've been given a file by someone who's using a bigfont you don't have and their text won't display, or they've got proxy objects that you can't detect or seemingly find.
You can use Properties Manager and QSelect to grab all text from your Entire Drawing (Mtext or Dtext) and delete it all very quickly, even if you can't graphically select it.
You can also do the same thing with AEC Proxy objects- provided you don't want them either!
Then, Purge away!