Doesn't have a measurable effect, and any negative effect will be imperceivable. Do whatever floats your boat.
Can't argue with magic.
I've read you should harvest before lights come on, but not sure if that was based on anything real or just more anecdote. Years ago i would turn off the light timer the night before a harvest, but nowadays i grow 8 plants at a time and not going to interrupt the dark cycle of the other plants. Years of doing both and i cannot tell a difference. So, even if there is a measurable statstically significant effect, It must be incredibly small and irrelevant.
Just because soemthing has a measurable effect or correlation doesn't mean human senses can notice a difference or that the effect is profound and worthwhile to be of concern. That's a seperate question for each context you look at.
For example, blue and red wavelengths have measurable and real effects on plant morphology that i will never debate, but it will never turn a short, squat plant into a stretched out plant, for example. Half my room is 2900K half is 3400k and again... relative to genetic diversity it is impossible to recognize the difference they have on plant morphology. i could assume things, but I have short plants under the red-heavy light and i have lanky plants under the blue-heavy light -- it's signifcantly more about genetics than the CCT of the light above them. Maybe, if i did a room full of clones i'd notice 'something,' but it'd still be a small effect. Use such things to your advantage when possible, but of little concern if you cannot. I.E. If i could see the future, i'd put the short plants on the red side and the tall plants on the blue side, but ... I do not have powers of foresight, lol. Once they grow through the scrog, which has a profoundly more beneficial effect, the plants don't move around.