The Night Blooming Jessamine that I am trying to root in water was one of the plants to develop a funk. I rinsed with 10% bleach solution, rinsed the cup with the solution, and replaced in cup with about an inch of distilled water.
The plant itself, while having a bit of the funk growing around the bottom, seems to be doing okay. No sign of roots yet, but no sign of death yet. They are still looking green and healthy.