tiny-secp256k1 and ECDSA signing determinism

[Bitcoin]

tiny-secp256k1 and ECDSA signing determinism

I noticed in bitcoin when using the tiny-secp256k1 library to sign the signature for a signature hash of an input; the signature is always the same.

However, the signature is always different in other ECDSA-Secp256k1 libraries. (I'm using one by nordic semiconductors.)

Do I misunderstand something? Is there a difference in the signature algorithms?

I read something about randomly and deterministically calculating the k value; should it matter if it is random or not? Or is there possibly extra encoding done after the signature hash is signed in Bitcoin Secp256k1?

Source: tiny-secp256k1 and ECDSA signing determinism