J key not working after setup

Hello, A bit of an odd occurrence today as multiple laptops / instances of examwritepad are having an issue where the j key will not register when typing on the document. It works when setting up - I.e when entering name, center number etc. But as soon as the document is ready to be used. The j key does not work. We are using the latest version of ExamWritePad. I have checked the .json settings file to see if there was anything accidentally checked, but I could not see anything obvious. I have attached our .json file Many thanks, Ben