The grammar in the BSON specification claims that the Timestamp type (0x11) is a signed 64-bit integer. In fact, a Timestamp is two unsigned 32-bit integers (time and increment, respectively), concatenated, effectively making Timestamp a 64-bit unsigned integer.

This should be corrected on bsonspec.org.

The MongoDB docs on Timestamp do not claim that timestamp is signed, so no change is needed: https://docs.mongodb.com/manual/reference/bson-types/

Pull request: https://github.com/mongodb/bsonspec.org/pull/46