This has to be a bug.
When you want to buy the carapace leggings box for bandit crests at the trader, you must have the story unlocked on the character. The other boxes do not need this. This was also not mentioned in patch notes.
I hope this can be fixed soon. I play the story on one of my characters, and farm bandit crests on another. Currently I have to leave silverwastes, deposit the crests in the bank, logout, login on the other character, go to a bank, collect the crests, go to silverwastes, buy the leggings, logout, logback in on the other character, go back to silverwastes. Though this is easier than doing the story, it is still a pain.