WTF

The number 4326785824919571000 is not the decimal representation of 0x3c0bd4c89186ca89.

Proof:

$ printf "%x\n" 4326785824919571000
3c0bd4c89186ca38

(Yes I tried other tools, from python repl to go playground to check the conversion)

It doesn't seem to be just a simple uint64 -> float64 -> uint64 conversion issue, since that would be 4326785824919570944, but it's close.

See https://play.golang.org/p/YdsUf5DjGy2

TODO: file a proper bug report