When hovering over 'o' in this sentence it plays 'velké o', despite one of these words not being in the sentence. Is this a beta bug?
I wrote Matěje and was corrected in the answer that it was Matěj. Isn't it Matěje in the Accusative?
Yes, "Matěje" IS the accusative. So there could have been something else in your answer that DL didn't like. It's helpful to post the entire sentence, so that the volunteers can identify why an answer was not accepted.