openssl failing to decrypt randomly?

Hi

I've been using this function to decrypt api account password in one of my scripts, and i can see it failing to decrypt in some machines. Different versions of macOS, i really can't see a pattern. Anyone seen something similar?

function decrypt_string() {

apipass=$(echo "$encrypted_string" | openssl enc -aes-256-cbc -d -salt -base64 -A -S "$salt" -k "$passphrase" )
}