Spread the word. Invitations are now world specific. They were before but you could get samples anywhere. Seemed to be a glitch. Others have said as well. Go to the worst planet in D2 (Mercury) to grind (and i mean GRIND) these stupid samples. Doing so now and i hate it. Cabal are iffy and Vex are easy due to the numbers. But Hive....Hive is a different story. That's a GRIND of a grind of a grind of rng. They have low spawn in forest and drops are not always guaranteed. So yeah...its gonna be a minute.