As ours always lived outdoors, we never had this issue but, being Border collies, they had that common BC habit of attacking things like lawn mowers, motorbikes or scooters if they are still for long enough. They wouldn't chase one but lawn mowers are slower so they'll attack those anytime they come into contact with one. It's something about small engines that sets them off. When people start bikes up, they really gets them going.

Now that Jess comes into the porch which is enclosed and carpeted and gets hoovered, we realised that she is also a hoover biter. I have to close her out of her lawn area when I mow it because she goes for the lawn mower really bad and she also has a go at the hoover now she comes inside so fear isn't an issue with ours. It's more them trying to grab the damned thing as you are pushing it backwards and forwards.

I don't think it's a big issue if the dog just goes and hides whilst the hoovering is being done. At least they are out of your way. Better than dogs like ours who want to keep trying to pick it up off the floor and going for it and getting in the way.
Maybe just let the dog hide and don't worry too much about it.