Took a cursory glance. Seems like you’re trying to put Gen 1 retail events into a Gen 1 VC save. That’s a no-no.
There is no legitimate way to transfer save between VC and retail cart.
In this instance, Bulbapedia’s documentation is not false, you just misunderstood what you’re reading and did something incorrect; you are doing something impossible and PKHeX is screaming at you, cause you’re at fault.
Edit: just to be clear, there are scenarios that PKHeX can’t perform meaningful validation on Gen 1/2 events, as those are so old and easily faked, and the documentation from Bulbapedia would not be enough for PKHeX to implement proper validation. But in this case, you're doing something beyond that.