I have what appears to be a Sterling Vikrell Ensemble Medley tub/shower surround in my apartment. On both sides of the enclosure, where the tub meets the walls of the surround there is a small gap and it seems that water is wicking or leaking into the adjacent wall. The problem is worse on the side near the tub spout. (See pictures) It originally didn’t have caulk, I then tried to put a bead of caulk along the seam, but the the problem more or less continues. I fixed the drywall and it came back over time. Does anyone know why this is happening and how to fix it correctly?