Dog barking when reversing car!

[KingKhazi]

I've had my 5 year old rescue havanese for about 6 weeks. She was rescued from a puppy farm where she was used as a breeding machine. So she's getting used to the real world still.

She's brilliant in the car, gets in and goes to sleep! However, as soon as the car starts to reverse she starts barking and won't stop. Her tail is wagging and she seems happy so it's more excitement I think. But why! It doesn't matter if she's been in the car a few minutes or for a couple of hours.
Tried ignoring her but she just doesn't stop which is obviously very distracting.

It's only when reversing! I've turned off my reverse camera as that beeps but that's made no difference.

What on earth can I do? I live alone so its usually just me and her in the car, and she's on the back seat with harness on.

I would just ignore her personally, as it's not like you reverse for hours - but I'm quite a lazy dog owner

I'd ignore it tbh, you get used to these little quirks.

She's probably barking because the car is doing something very unexpected, which is quite alarming (wagging tail doesn't always mean a happy dog by the way - it's the biggest myth going - it can be emotional arousal).

Mine barks when we stop at traffic lights - but only if we're at the front of the queue. If there's a car in front he seems to understand why we aren't moving, but a red light isn't good enough for him and he gets frustrated!