Yes, I see it in that testcase, and also if I make the sentence "The quick brown foxx jumped over the lazy dog." wrap to several lines so that "foxx" does not appear on the first line. If, however, I misspell "lazy" as "lazzy", and that's on the last line of the textarea, it will be OK. So it appears that the misspellings have to be there already, and have to appear not on the first and not on the last lines of a textarea, for this to fail.
Yes, I see it in that testcase, and also if I make the sentence "The quick brown foxx jumped over the lazy dog." wrap to several lines so that "foxx" does not appear on the first line. If, however, I misspell "lazy" as "lazzy", and that's on the last line of the textarea, it will be OK. So it appears that the misspellings have to be there already, and have to appear not on the first and not on the last lines of a textarea, for this to fail.