Can you not say 'this is a hat'. I thought 'das' could mean 'this' or 'that'.
A week has gone since BookReader26 has posted, but "This" is still not accepted. I suppose he did not report it. So I did.
I'm afraid that a week is very optimistic.
Even for the sentences from the public course that we volunteer contributors maintain, it can take quite a while before we see a report -- there are simply thousands of sentences and thousands of reports and we can't get through all of them in a timely manner, especially not if we also try to look into sentence discussions and answer questions.
However, this sentence is not from the public course; it's from the Pearson cooperation ( https://www.duolingo.com/comment/24052907/Duolingo%E2%80%99s-Partnership-with-Pearson ).
I don't know how quickly they look at reports for their sentences or how many people they have working on them, but it might take a while as well.
Still, I recommend that you report any errors you find in "their" sentences as well.