I know for a fact (seen it from the inside) that many so called "seed banks" simply horde together a few dozen different cultivars at most. Then market them as such and such, la de da, and oh yea, got that one too... we carry ever rare seed on the face of the earth.... all 10,000+++ strains...
Unscrupulous people are making a living this way, I personally know a few. I won't do it, but it wouldn't be difficult.
This is literally a billion dollar problem, annually...
It's a widespread problem within the commercial market. I would stick to reputable long standing sellers who've stood the test of time, or hobby growers such as can be found here, and judge things the by the actual grow logs... Known entities. Get to know who your dealing with...
It boils down to this: Some people are inherently dishonest, especially when it comes to $$$...