Buffy only stopped being in Walsh's class because Maggie tried to kill her and then was herself killed by Adam
Buffy was in Walsh's class in the fall semester - which ended in December (for reference, "Hush" was the last episode to air in December). In fact, in "A New Man," Buffy's already gotten her final grade (B-). Unless she was taking a second semester of psych (which there's no evidence of - we don't see her in class after the "Hush" dream sequence), she wouldn't have had Riley as a TA in the spring anyway.
As I said, it's probably inappropriate for Riley to be interested in her when he's her TA, but the actual relationship starts after the class has ended.
no subject
Buffy was in Walsh's class in the fall semester - which ended in December (for reference, "Hush" was the last episode to air in December). In fact, in "A New Man," Buffy's already gotten her final grade (B-). Unless she was taking a second semester of psych (which there's no evidence of - we don't see her in class after the "Hush" dream sequence), she wouldn't have had Riley as a TA in the spring anyway.
As I said, it's probably inappropriate for Riley to be interested in her when he's her TA, but the actual relationship starts after the class has ended.