The current EX pass invitation system is broken. To say the least not transparent. This resulted in many hardcore players around the world not receiving any EX invitation. Whereas Niantic has been speculated to try to lure back players who are softcore by giving them invitations. If this was the case, they need to fix this. Regardless, make all your invitation process es transparent. For example, in Singapore, Brandon Tan who has the most raids in the world did not receive any EX pass till 3Nov(not clear as of today). Many accounts of people in the same gym same raid boss raided together only one out of all of them did  receive EX pass. The probability is extremely slim. Transparency is much needed. Everyone raided the same raid boss should be invited.