Crop an hash output isn't like produce the same lenght hash output

[MikeRow]

Hello, considering the minimum hash lenght 16 byte, and needing 5 or 8 byte of hash lenght, I've noticed that crop the 16 byte to 5 or 8 doesn't produce the same output.

For example, using https://github.com/strawbrary/php-blake2 (which allows me a <16 byte hash output) the result is good.