Why can people use unlocked weapons if the servers are bugged?

Basically the title. Why can some people use weapons unlocked through progress and some cannot when the servers are bugged? Ara the servers bugged for some people and for some people not even though we are on the same server?

Basically the title. Why can some people use weapons unlocked through progress and some cannot when the servers are bugged? Ara the servers bugged for some people and for some people not even though we are on the same server?