What's the data supporting this 20-person cap? I see this thrown around, but I have yet to see a source.

Anecdotally, I've seen more than 20 pots after the fate, and I've also completed the Pots fate with only three people and two of them didn't get a Pot buff.

I'm asking because it feels like someone said "20" and everyone else just takes it as the word of god without questioning it.