Frothy/bubbly discharge but not trich or BV?

Does anyone know what could cause frothy or bubbles in my discharge, but having ruled out EVERYTHING (STIs, BV, yeast, ureaplasma, mycoplasma, strep, etc etc etc). Normal flora according to Microgendx test. The only finding is excessive, frothy discharge and high white blood cell count (which makes it yellow-hued).