You haven't even begun to enter the world of unscrupulous activity, and Amazon is mostly 'hands off' because they don't care - but other 3rd party sellers DO and they know all the tricks about how to pump alternative sellers off the page, etc.
The whole thing is a worthless Alibaba ripoff now.
Do you think some other seller falsely "reported" me, claiming my copies my be counterfeit, for surely there was no way I could offer them so cheaply to beat out the next cheapest seller by, what, 50 cents?
Your case is interesting because your publisher was fine with it. So yeah, it probably was done by a third party seller. Or you triggered some automated system and will never find out why. There are cases where third party sellers bribed Amazon employees to penalize their competitors:
> "(b) using their inside access to Amazon’s network to suspend competitors’ 3P accounts; and (c) providing consultants with information about Amazon’s internal algorithms, which allowed the consultants to flood competitors’ product listings with fictitious negative product reviews."
There's another thing where well known brands will hire a company like https://amazzia.com/brand-protection-2022/ for "brand integrity." In reality, what this means is that they monitor Amazon for listings of the brand's products that violate the brand's Minimum Advertised Price policy and then report them a bunch of times as counterfeits or contact some Amazon employee they have a (potentially corrupt) relationship with.
Or maybe some machine learning deduced you were "counterfeit". Who knows. The common denominator is - Amazon doesn't care, it's just a machine, even more so than corporations by nature are.
The whole thing is a worthless Alibaba ripoff now.