As a manager, my recommendations for resolving this conflict would be to first have a private conversation with Lisa to understand her perspective and feelings about the situation. It is important to acknowledge and validate her feelings while also explaining the impact of her comments on Maria. Then, I would facilitate a meeting between Lisa and Maria to have an open and respectful conversation about their differing viewpoints and how they can work together effectively despite their age difference. It may also be helpful to provide training or resources on cultural competency and respectful communication to prevent similar conflicts from arising in the future.
I have experienced a similar situation where a co-worker stereotyped based on a generational attribute. One of my colleagues, who was in his fifties, made a comment about how younger employees always want things handed to them on a silver platter and lack work ethic. As a younger employee myself, I felt frustrated and disrespected by this comment.
To prevent this in the future, I recommend promoting open and respectful communication among all employees and emphasizing the importance of avoiding stereotypes and assumptions based on age or other demographics. Encouraging diversity and inclusivity in the workplace can also help prevent stereotyping and promote a more positive work environment for all employees.