Small groupings of people drawn from populations that are heavily weighted toward white male English speakers organically selected are unlikely to be more diverse than the population its drawn from and many groupings will end up distinctly unequal even without bias being involved.

If you imagine dealing out people like cards into stacks chosen randomly and enumerating the demographics of each stack then large stacks would tend towards the population demographics but many smaller stacks would have all sorts of distributions. The only way to ensure a small group is diverse or a large group isn't is to select them for immutable characteristics instead of skill.