Problems in the DuoLingo database ?

What is happening with the DuoLingo database ? Recently the number of my "mistakes" has been growing rapidly and I am losing so many hearts in the exercises that I have to repeat them two to three times to complete them successfully; I think losing 40 percent of your hearts learning something new is acceptable but 50-60 percent in all exercises is frustrating and counterproductive!
A few of the goodies: "Lo hemos citado" Duolingo translation: "We have set an appointment for him." If you translate "los niños" with "the children" you are told it must be "the kids" etc. Feedback does not seem to have much effect Does anybody else have similar experiences ?