Says words that are spelled correctly are incorrect!

I use to love this app but lately I have been finding that it will say a word is spelled incorrectly when it is correct. This is extremely frustrating and completely negates the purpose of the app. I have found that it is typically when prefixes and/or suffixes are involved (eg unfortunately) Please fix this bug!

Jonpsfd28 about Speller - Free Spell Checker, v1.6