Vulnerabilities misspelled in US dictionary

Has anyone else run across this? When I put the word vulnerabilities in a new e-mail or IM Notes says it is misspelled and wants to spell it vulnerabilitys. I have tried it on a few clients at my workplace and they all seem to have the same problem.

As a workaround, I added the correct spelling to my user.dic but, with this method, it will not mark vulnerabilitys as incorrect if typed.