GCFI flashes red once when turned on

I understand what a solid red or blinking red light means, but there’s no documentation for it flashing once and turning off. I have it attached to a light switch, and each time I cycle the power off and back on, the light will flash red once. What does this mean? I have a receptacle tester plugged in, but it never lights up for even a split second. Pressing the test and reset buttons does nothing.