Thank you for your post.
I am unable to replicate the issue using your exact steps.
What browser are you using to access the database file? What version of the browser? In my case, I have tried it with Internet Explorer 11, Safari 8.0.6, and Chrome 43. With a file hosted by FileMaker Server 14, the screen shot below shows the file accessed by FileMaker Pro 14.0.1 on the left, and the file accessed by Web Direct using Chrome 43 on the right.
I am really sorry.
After I have seen your post, I have recreated the calculated field with a new name and tried again.
The newly added one is rendered correctly but the old one is still not.
I do not know what did I changed for the old one but no problem. I will delete it and continue with the new one.
Sorry for taking your time.
No apology needed! Your solution may help other users who run into a similar situation.