Since when "Frage" means "issue"?
When "die Frage" means "das Thema" (topic) it can be translated as issue. "Issue" has quite a lot of meanings and translations.
So the word has two meanings?
However you will find very very few cases where you properly translate Frage into issue
Why is "issue" feminine?
It is its gender. You see, it's not the actual person, place or thing that has gender in German, but the WORD that stands for the actual thing. That's why a “car” can be either das Auto (neut.) or der Wagen (masc.).
And that is why Duo is great. Because of commenters like you.
Ah ok thanks.
Why shouldn't 'Sache' be allowed?
It allowed. I used it and I was given right.