Hello Prajakta,
Let me give you some updates. Currently, we have two issues. One happens with ArrangeData, where, sometimes, date values are being converted to datetimes and the other happens with JSONSerialize (default values) not making 1900-01-01 dates null.
Regarding DataGrid, we can only fix ArrangeData, therefore we have an issue on our backlog to tackle this bug. It should be fixed by our next release.
We are sorry, but as of now, there is nothing else we can do to help you.