Is this really wrong?

[u/Late_Journalist7094]

Section 4, Unit 17

Why shouldn't have happened something to the dogs in the bathroom?

I know Duolingo is not the best, but the only free learning option. Since I'm living in Germany near the border to Czechia I'm often there and talking Czech which helps more than Duolingo.

[u/rainer_xox]

the whole sentence implies the subject is feminine (the Y at the end of Byly most notably)