Does it look bad if I get a rec letter from my supervisor who I worked as a Research Assistant under instead of the PI? I worked very closely with my supervisor and her letter is strong. I did not develop as strong of a relationship with the PI. It has also been a year and a half since I've left that job and I have not reached out to her once so I feel uncomfortable asking her to write me a rec letter. My supervisor already has one written for me as I have asked her to write one for a couple of summer programs I applied to.