Thanks for the suggestion JMichael. Turning off "correct spelling automatically" as you suggested fixed the problem. (I'll see if the setting stays across notes and after I restart EN, but I'm optimistic.) Still, I think the functionality should be clearly listed under Parameters/ Settings.
+1 on the request for an app-internal setting to turn on or off autocorrect across notes. It's particularly problematic for those of us taking notes on topics with acronyms and jargon, or writing notes in multiple languages.