Really sure the LED blinks only a short time, but not 100 % sure the exact duration of the pulse. The frequency is between 24-25 Hz (checked with oscilloscope during current measurements and optically with a 960 fps camera). The “blinking” is visible by eye and it can be observed, that the LED is on at max one of the frames of the camera (so pulse is shorter than 1 ms).
As mentioned above, the current measurement show, that the pulse duration is around 16-18 us, but due to the low bandwidth (300 kHz) of the uCurrent, the exact values of duration and especially amplithude are to be questioned.
If I find time soon, I will try to probe the LED directly with the oscilloscope, to get better values of duration (but will add no value to current obviously).