Two errors during testing in Italian:
I'm on a Mac using Google Chrome ver33
===2=== In this second error, I got marked wrong for an answer but it didn't highlight anything wrong or give any explanation of what was wrong with the sentence which should be using the essere verb rather than the avere verb for this tense.
Despite what the link is named... this screenshot was taken on Feb18.
===1=== EDIT: I just realized this isn't an error. But instead my mistake of misreading the very subtle differences in multiple choice options ('lui' instead of 'lei').
In one instance that just happened today, the Italian skill strengthening test gave me two identical multiple choice answers. I chose both but was marked incorrect. (This happened to me before where all three choices were identical... but I don't have a screenshot of that.)
Taken Today, Feb26
Sorry, I don't take Italian on Duolingo, but you could report this by clicking the "Support" button on the side of your screen.
The system doesn't highlight the error if it cannot recognize a closest translation. In your case, there were too many differences to indicate exactly what the problem was.