This is in regards to JAVA-1741. Please document change in behaviour of java driver (v3.0) in regards to inserting java.sql.Timestamp or java.sql.Date.

jeff.yemin has said in a comment that:

It's a mistake that the 2.x driver encodes instances of java.sql.Timestamp, as it silently drops the nanosecond field that's present in that class. We plan to document this backward compatibility break, and suggest that users prepare for this by converting Timestamp to Date, e.g. new Date(timestamp.getTime()).