I did flow cytometry using the same probe (DCFH-DA). I had not problems with Ehrlich cells auto-fluorescence. Maybe, you should check the lasers parameters.
Mosiman, V. L., Patterson, B. K., Canterero, L. & Goolsby, C. L. Reducing cellular autofluorescence in flow cytometry: An in situ method. Communications in Clinical Cytometry 30, 151-156,