The red highlighting for invalid typing answers is incorrect. When the typed answer matches any sequence of the following string: “You answered:”, the incorrect characters are highlighted.
As example:
When typing: “ans”, the button “Veryify/Next” is clicked and the typed answer is incorrect, instead of highlighting the invalidly typed answer, part of the “You answered:” is highlighted.
One image is attached to show what I mean. I hope it’s clear 
(I could only add one image as I’m a new user 
but the invalid highlighting goes as far as the whole “You answered:” string)