I won’t say their name because that would indirectly identify me but they left Amazon to teach a few years ago so this information could absolutely be outdated.

Amazon uses an offline item to item comparison table. Every so often it will collect all items viewed or bought by people who bought this product to make a table of what to recommend. If an item is added right before this information is pulled, it’s likely to have a small sample size. This will then remain til the next update. So it’s possible this was based off only a handful of people making the results very skewed and that it hasn’t updated since.

Source: my professor who helped design Amazon’s algorithm