That is unrelated to GoV. Characters receive less exp they are a lower level than the highest level character in the party. If this amount is reduced so much that you receive less than 1 exp, you won't get exp for the kills and therefore the kills do not count towards page completion.

I just did a few levels in Onzozo today with a friend's mule. I was level 72, he was 17. He gained 13 exp where I gained 40ish, so it is pretty reasonable that this could be reduced to as much as less than 1 when first, a level 85 character typically get even less than 50 exp in a party of two on EPs, and second, the level difference is even greater.

Even in normal GoV alliances you can get pretty close to just 1 exp per kill, even when everyone is roughly the same level. I've been in CN alliances where i got 4-5 exp per kill :/.