Inbound SAML add extra unwanted custom attributes to profile

I have setup Inbound SAML to integrate with an external identity provider and am find that extra unwanted attributes are being added to the profile.

The external IdP will be providing the attributes; givenname, surname, and emailaddress. These are the ones I’m requesting as required and in profile mappings Mapping to the corresponding Okta User Profile attributes.
Yet what is happening is that at some point the Inbound SAML is adding the extra unwanted custom attributes firstname, lastname, email, and mobile.
The first 3 are flagged as required and they are all being mapped as well. These unwanted attributes are appearing as requested attributes in the SAML generated and are set there as required.

The external IdP we are getting security responses from does not have these unwanted attributes and will not be able to provide them in the response inbound saml.

I consider this a bug as it results in an unintended configuration that generates SAML metadata this is unusable. The custom attributes being added are not valid for purpose and I am unable to prevent this.I have setup Inbound SAML to integrate with an external identity provider and am find that extra unwanted attributes are being added to the profile.
The external IdP will be providing the attributes; givenname, surname, and emailaddress. These are the ones I’m requesting as required and in profile mappings Mapping to the corrisponding Okta User Profile attributes.
Yet what is happening is that at some point the Inbound SAML is adding the extra unwanted custom attributes firstname, lastname, email, and mobile. The first 3 are flagged as required and they are been mapped as well.
These unwanted attributes are appering as requested attributes in the SAML generated and hare set as required.

The extertnal IdP we are connecting to will not be able to provide these extra attributes so the inbound saml will fail