brainhurt
For the record I was joking around, there grammatical error means nothing other than they need better QA.
Ok, web programmer here. There's only one web page template that the server uses to show that "Thank you" message. In other words, it's impossible that everyone has their own page that requires little elves to fix it one by one.
Guess what? Try to delete your browser history and see if the grammar is fixed now. Most likely, YOUR BROWSER CACHED THE OLD/INCORRECT PAGE and that's why everyone sees a different version.