MS Outlook functionality especially editing is totally broken - for example, if you select a word and dictate a new word to replace it, the old word will still be left behind. Siri dictation, which is getting better and better, still falls far short of this in my opinion.
This has been present for several versions. It randomly starts leaving an extra letter for me as well sometimes. If so, did you notice any significant differences? Also, is there any way to write a command using the function key? I think that is why scrolling never works on Safari. Does anyone have any experience using Dragon to navigate a web browser on a PC and a Mac? It has quit on me a few times, and sometimes the dictation will randomly start adding an extra letter until I restart my computer, but it sounds like nothing compared to the earlier trials you went through. I have cubital tunnel syndrome which has made typing and using a mouse very painful. Your best bet might be the Dragon Riders group on Facebook.