I'm currently using this setup:
Solar bank with 3x600 panel on the surface, switch chimney connecting down vertically in the same chunk, everything else on bedrock level. Battery bank has a random collection of 4 green to purple batteries.
Connections are this:
solar bank -> switch (x6) -> battery bank
battery bank -> switch -> fridge
battery bank -> switch -> insect light -> rodent repeller
Everything turned on.
When the early morning arrives (3:59 a.m. to 4:00 a.m.) we can observe the visual effect on both the insect light and rodent repeller change so they look turned off. Without intervention and having a wire tool in hand, all of the appliances show powered when hovered over. On restarting the game, the insect light and rodent repeller show the correct visual effects again.
https://imgur.com/a/hnpKo
For this quick test, I can provide some screenshots.
I have pretty much the same setup running this way for several ingame months, not once, but four times. Twice on my laptop, twice on my home pc. For the kitchen and for the survivor village. The screenshots are from my laptop as well, which explains the graphics quality, please excuse.
I've experienced the visual glitch, which it for me luckily seems to be, reproducably every morning for months ingame and most of the time it has been ignored without intervention, seeing the lights turn on again not only after re-entering the game, but also after re-entering the base after looting or horde night adventures.
However, at the end of last year, I was playing a different save on a harddrive that has since perished and I DID experience crop spoiling there, though the setup was pretty much identical.
I've been playing singleplayer exclusively all the time.
On the last image of my screenshots you see a generator bank near the insect lights. That one hasn't been connected since I got my hands on good solar panels.
edit: In your situation, I'd recommend the following:
1. Put the best 6 batteries you can find in your battery bank and have it powered by a generator with a good fuel tank (small generator gives 1500 instead of 1000 on the generator bank, no idea about the diesel generator, haven't built one in a while). Powering only the insect lights and rodent repeller.
2. Produce only small amounts of food and then store them where it doesn't spoil. I know it's considered cheating and we don't talk about details here, but I'm sure you know what I mean. In your case, you're experiencing a bug AND you already built anything needed that should guarantee you unspoiled food AND you're in singleplayer. So in my personal opinion I can see nothing wrong with doing that. Alternatively, turn off food spoiling the moment you acquire solar panels. If you know how that's done.
edit 2: I got three questions now, PPanda0421:
1. If you did the same test (wait for the insect lights to visually turn off in the morning), will hovering over it with a wire tool show it powered or not?
2. Since this turned from a real bug (in December) to a visual glitch (right now) for me, is it possible that it also changed for you and you're over careful now, because you experienced spoiled crops and food in the past?
3. Are you aware that insect infestation will appear on your crops with fully functional insect lights, if you leave mature plants unharvested for too long?