Very bizarre, and seems no one reading, me included, meets your call to those with a similar experience.
Did the doctor visit include taking a sample of the discharge for laboratory analysis? I should have.
Think to about anything different about your life-style and practices that started about the time of this symptom. There may be an external or ingested cause.
Have your doctors simple given up? I don't understand this if you have been able to produce discharge for them to examine, sounds like all you have to do is lean forward.