Are ECC CSR always different and if yes, why?

Are ECC CSR always different and if yes, why?

I've noted that SHA256 of CSRs for RSA keys, generated as

openssl req -new -config leaf.conf -key rsa.key rsa.csr

are always the same, given the same key and configuration. In the same time, every time I regenerate CSR for ECC (P-384) key, I get different SHA256 sums:

openssl req -new -config leaf.conf -key ecc.key ecc.csr

Why is this happening?