When rules and laws conflict in real life or in a game I usually go to the highest authority, in this case I think the core rulebook is that source. I have always played with that you only have one buddy and never even read the quickstart rules. The other thing we can do (and this is actually the Swedish judicial system) is to interpret the intent of the "law" or "contract". Let's think about why this mechanic exists. I think that it's crystal clear that you shouldn't be best friends with everyone since then you'd pretty much get exp every session and helping a particular person would not have any significance. Having a game mechanic that encourages helping one player more creates or encourages social dynamics, the other way around is, as I said just a free exp grind.
But if you want an official reply if it's a misprint, well, I guess we have to wait and see when Free League replies.