"... the fatigue" is slightly unnatural English. Just 'fatigue' would be better (but of course it is not accepted).
Yes. It helps to have the article "the" for the reverse translation, but it is more natural to say simply "fatigue." That answer is now accepted too. Thanks!
It's annoying when there is not option to submit that my answer is correct. "I see that fatigue is settling in" did not contain a typo and should be a totally accepted answer.
Try reporting it. There are so many variations and “I see fatigue is setting in.” was already accepted as correct.
Is "the fatigue settles in" (or settles down) not correct? I'm not sure if I need to make it a progressive tense.