Your data is bad as you have already noted. The problem is that the driver is trying to expand the date value ( which is really just a number internally to mongo within a BSON timestamp field ) into a real DateTime object.
When it tries to do this on read, the number is invalid an the inflation fails. If you fix the date value the problem will be corrected.
Note: If you do this in the shell use the ISOate helper to put a correct value in. If you use code then use a DateTime object. Don't use strings as you will mess your data up further.