Yes, it does take an image at 0.001 seconds. EKOS shows Capturing at 0.001-second image..., and the image is saved as Test.Light.0.001_secs.001.nef, and the actual image has an exposure of 0.001 seconds.
If I try to set a different exposure in EKOS, say 0.01 seconds, Ekos shows Capturing at 0.01-second image..., and the image is saved as Test.Light.0.01_secs.001.nef, but the actual image has an exposure of 0.001 seconds.
If I try setting the exposure to 1 second, the results are the same as above.