I knew that Drama profs are programmed to be in love with their students before I had my Sim start a relationship with one, but I don't remember seeing this problem before.
Drama profs get the floaty crossed-out double smileyface above their heads whenever they have an interaction with someone who isn't their best friend. This isn't limited to students, either. They also get a "lost Sim as best friend" memory for EVERY interaction. This stops when they actually become best friends with the Sim, but they end up with hundreds of losing best friends memories. Before Nightlife, I've seen Sims interact with Drama profs without the floaty smileyfaces and memory spam.
Drama profs, even after you move them into the base neighborhood, fall in love with EVERYONE they meet, and keep adding to their "lost best friend" memory collection.
Maybe the patch fixes this, but I see an early grave for my "confused" professor