I noticed a few months ago that if I would put things in my cart and not order them right away, the price in my cart would jump a lot without notice, but the price on the page would stay the same. Like, I added something that was $30 to my cart, 2 days later it was $50 in my cart but the store page still showed the price as $30 and there wasnt the usual "an item in your cart changed price" message. I had to delete it from my cart and re-add it to get the price to drop. There was no deal, it wasn't subscribe and save, nothing. This happened multiple times. I also had prime and couldn't tell you the last time my shipping took less than 2 weeks, and I live near a city. I've since canceled prime and stopped ordering from Amazon unless I can't find what I need elsewhere. Want to scam me, fuck you.
I'm not surprised to hear of strange happenings like that.
There were a few months several years ago were I'd randomly have like THOUSANDS of a single item added to my cart. Stuff I'd never order, never wish list, and never searched for.
Sometimes my shopping cart would have like $15,000 worth of stuff in it.
They couldn't explain it, and the mystery was never solved.