Student satisfaction surveys are widely accepted for measuring the quality of students' overall experience with the received teaching and informing the design of improvements in higher education. However, several studies have shown that these surveys have biases that may lead to discrimination or unfair decisions against female academics. Yet it is unclear how these undesirable factors are evolving with time or to what extent they are present in different contexts. In this study, we investigate survey results from a large University in Spain for two academic years, 2021-2022 and 2022-2023. Our analysis examines these gender biases by evaluating the influencing factors from the perspective of professors and students at the level of the entire university and individual centers. The results obtained using this approach provide multifaceted evidence of gender bias disadvantaging women, especially in some academic disciplines, and that is particularly noticeable in the extremes of student satisfaction distributions.