What kind of ballast do you have? is a reactor type or a CWA (constant wattage autotransformer)? A reactor is more sensitive to voltage fluctuations than a CWA. Some of the Home Depot, Lowes, etc economy types use the more economical ballast, resulting in these kinds of problems. When you replace the entire fixture, go to an electrical supply store such as GrayBar to get your replacement fixture.
