Here's a hunch.
A guy showed me a trick. We were discussing fluorescent lighting, specifically magnetic versus electronic ballasts. He showed me how to determine the type of ballast being used by using the camera in his cell phone.
Looking at the camera image on his phone's screen, and aiming the cam directly at the fluorescent tube, the magnetic ballast caused black lines to appear on the tube. The electronic ballast didn't do this, and the tube appeared evenly lit.
That's a new hotel, so magnetic ballasts aren't used. However, you might use your cell phone cam to see if the dark lines are present. And you might narrow down which light fixture is responsible. This is a very simple and easy test to perform, and might yield some clues.
Another thought:
maybe those are dimmable lights, turning on and off with a varying duty cycle, to adjust the light level. If the lights are not set to 100% illumination, then they may be off part of the time, eg: 50/50 duty cycle
Good luck
Fastb