The data and user flows for three types of Seamless Access integration options (Limited, Standard and Advanced) are described in the presentation available at:

Based on this: GEANT Data Protection Officer have given following evaluation conclusion:

On 14. February 2020, for limited integration:

"Then, taking into account all the information provided, there is no processing involved."

On 1. April 2020, for standard and advanced integration:

"In case of Standard and Advanced integration there is no processing from SA part (as there is not even a technical log) – there is processing which is done by the entity providing scholarly resources (and home institution providing authentication).  

Apart from that the information provided here is more than sufficient."