Sorry I'm unable to reproduce with FF35. Using spell as you type there are no 'junk' warnings in the console.
I am using 4.4.0m, so slightly newer script than you have. I can send you mine if you would like, but are you referencing the script file directly, or is your import using the Servlet, eg <script src="a.rapidspellweb......."
Otherwise if you could see if you still get the problem in a trivial page please.
Thanks
Jim
-your feedback is helpful to other users, thank you!