I found an inconsistency with the Vault+ rank benefits. Vault+ is supposed to allow resource downloads for 1 Shard, and the resource page correctly shows "Download Cost: 1 Shard." However, when attempting to download, the website displays "Insufficient Shards" and says that every resource download costs 2 Shards, preventing the download unless the account has at least 2 Shards.
It looks like the download validation is still using the default cost of 2 Shards instead of the 1 Shard benefit provided by the Vault+ rank.