Interactivity - Text corrector page template

Not sure if this is a bug or incorrect set-up. Anyone seen this happen before?

Set-up a text corrector page (see link below) but it isn't correcting the text. Do the words need "mark word"? On the first page in this LO I set-up a simple example and that does work if the user enters the correct line.

When I used the Page Types demo for text corrector, even with the correct and answers it comes back incorrect. I was copying and pasting the correct answer into the box.

Link to example: xerte.cahss.ed.ac.uk/play.php?template_id=1217


Thanks in advance
Alison