Translation:The child has dropped the big book intentionally.
"The child has intentionally dropped the big book", is what I put. Same meaning, different word order; marked wrong.
Also, "The child dropped her big book intentionally," was not accepted, insisting on "...has dropped..." Both mean the same in English.
There are tools in the report system that help us to see when we have the matching translation, so it's easier to deal with there. As far as I can tell your translation is there and something went wrong. But if I had your translation in the report system I could check in a more exact way.