Order of Primarch Rediscovery

A while ago on the First Expedition Forums, the Black Library released the "official" rediscovery order of the Primarchs. I'm reproducing it here for reference:

1) Horus Lupercal
2) Leman Russ
3) DELETED FROM IMPERIAL RECORDS
4) Ferrus Manus
5) Fulgrim
6) Vulkan
7) Rogal Dorn
8) Roboute Guilliman
9) Magnus
10) Sanguinius
11) Lion El'Johnson
12) Perturabo
13) Mortarion
14) Lorgar Aurelian
15) Jaghatai Khan
16) Konrad Curze
17) Angron
18) Corvus Corax
19) DELETED FROM IMPERIAL RECORDS
20) Alpharius

Hence the only primarchs whose discovery order is the same as their legion number are:
Rogal Dorn and Alpharius

I kind of like this order, but there are clear conflicts, of cousre. But as the OP on the forums stated, there's a wibbly wobbly timey wimey thing at play rather than any canon error…..!