It's not clear how it detects which type you've passed, but this is pretty unexpected:
`{"local":"0099-12-31T16:00:00-08:00","unix":-59011459200,"utc":"0100-01-01T00:00:00Z"}`
This too:
`{"local":"8675-11-04T16:00:00-08:00","unix":211615977600,"utc":"8675-11-05T00:00:00Z"}`