Error message «invalid answer” before answering the question

Hi there

I am a new user of Articulate and created a new question slide for the first time with Storyline 360 and selected Harmony as layout. If I want to look at the scene in preview mode, the message «invalid answer» appears BEFORE the question. Only when I click OK, I can answer the question. In my opinion, this message should appear if you haven't selected any answer and want to go to the next question – so AFTER the question and not BEFORE the question.
Do you have any idea why this message appears before the question?

Thanks a lot and kind regards!
Veronika