There was a minor mistake in the code. Internally this filter is called both require_corrected and requirecorrected (please don't ask why). There then is a function that translates the internal name into something readable. It's called with requirecorrected, but was only translating from require_corrected (which never matches). When it doesn't match anything, it replaces underscore with space and uppercases the first letter.
I have fixed this in the development environment. Should go live with the next release, and that will also fix translations into other languages.