Hi, I don't know if it's a bug or a deliberate commercial policy, but I thought I'd report since it is annoying.
We have a team account with private repositories and a 10 users limit. The problem is when a team member makes a fork of one of our private repositories, they doesn't inherit the team's 10 users limit; instead, they get the "You're over your plan limit. Committers have read-only access" message over all their pages.
This means that the "fork" feature becomes less useful than it should be, even though we have paid enough for our current team member count.