Vandal and sock puppet
Please watch out for this user: https://www.duolingo.com/#TheFrenchGuy102. This user has recently changed from user names TheFrenchGuy101 and GuyFrench101 (but Duolingo changes the user name displayed for posts and translations). This person also has a sock puppet (duplicate account) at https://www.duolingo.com/#TheItalianGuy101.
This user has been persistently vandalizing the article https://www.duolingo.com/#translation/d5bb08545ba0755ac86a52ddacb9639a$index=21 (Rosetta (sonde spatiale)) for several days. I and others have already reported this user. Please stay on the alert, monitor, and report as you are able. Thank you.
EDIT: The user is also active at the 90377 Sedna article (English-to-French): https://www.duolingo.com/#translation/2528afdc86bb5a8b2337c848fb63b3fe. The vandalism is not as severe, but the user has made several translations that appear to be intentionally shoddy.
Looks like you and some others are doing some good, thoughtful work with the Rosetta article. I love how you guys are making comments and working together. It makes the document a pleasure to read.
What a shame some folks have nothing better to do than ruin things for others. I see he's also being quite rude to you on your profile. You can block him if he bothers you too much. Click his name to go to his profile and then click the little pale gray gear to the top right of his avatar.
Thank you for the support and advice. For now, I will leave the user unblocked just to see his or her activity and be better able to "play defense" for the site. It's no bother to me; the user appears to be just a middle schooler goofing off at our expense. Perhaps he or she will tire out or be encouraged to start to enjoy Duolingo for its intended purpose.