[2019] World Tier 5 unlock?

I am not lvl 30 yet but i wanted to ask a question about the world tier system. Is it true that you can visit a vendor once you move to the next tier and instantly buy the gear you need to reach gearscore for stronghold and invaded missions? I 've read that somewhere and i think that if true then its an oversight from the developers that needs to be corrected. (i know i can opt not to buy that staff and that is what i ll do, if that is the case, but still it should not be like that)