SAML response contains RSAkeyvalue, was it always the case?

Getting advice
1

Hello, is that was always the case that SAML response will contain RSAkeyvalue when signing the document or the assertion? seems like some SP don’t like that " I know they should fix their code" I was just wondering if this was always the case, an example is below " some parts are omitted "

    <dsig:SignatureValue>XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX</dsig:SignatureValue>
    <dsig:KeyInfo>
        <dsig:X509Data>
            <dsig:X509Certificate>XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX</dsig:X509Certificate>
        </dsig:X509Data>
        <dsig:KeyValue>
            <dsig:RSAKeyValue>
                <dsig:Modulus>XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX</dsig:Modulus>
                <dsig:Exponent>AQAB</dsig:Exponent>
            </dsig:RSAKeyValue>
        </dsig:KeyValue>
    </dsig:KeyInfo>
</dsig:Signature>