It’s an issue with unique items and how the warbank counts as part of your inventory.
If you have 15/20 memories in the warbank and log onto a character with 6+ memories in their inventory they won’t be able to see them, but the memories are still in the warbank if you log onto another character without too many unique items.
Basically either delete some memories out of your inventory and relog so the warbank refreshes, or log onto another character and remove enough memories so it adds up to 20 for the char you want them on.
Or just mail them which actually works as intended.