It's pretty apparent that the photo was taken with a dedicated flash, which is a whole other gadget than the little pop-up flash on your average compact.

A good flash is not just a lot more powerful, but can operate in sync with the camera, and be adjusted to deliver just enough light for the shutter speed, aperture and ISO that the camera is set to, so that you get a natural exposure. You often use a flash with a diffuser or softbox to spread the light out and create a more natural exposure.

To start, there's obviously a visible reflection of the flash to the right of TH. It's tripled because of the curvature of the door. Her body cast a hard shadow on the car, which is a solid sign of a flash being used. And overall, her face is a bit more filled-in with light than you'd otherwise expect in natural light. As for her clothes, the whole photo looks a bit underexposed, and in combination with the flash, you end up with a fairly high-contrast image. Black is also a very dark colour to start with.

Judging by the overall brightness of the photo and the sunlit reflections in the windows in the background, I'd say it's late afternoon with the sun still a little way above the horizon, but not quite sunset.

A good flash used correctly won't necessarily be evident to a non-photographer, but it might induce a certain subtle look (like shadows that don't line up with how the sun is angled) that makes it "feel weird" for reasons you can't explain. I suspect that's why you're having issues with it.

Lastly, I don't know why everything needs to be a conspiracy on this subreddit. One reason not to use the photo on the flier is that it's not a great photo to use. In situations like these you'll want a fairly neutral, contextless portrait photo that's already the right size and resolution. Secondly, they might not even have had access to the photo at that point.