I am sure this is quite minimal, but it gets irritating from time to time.
When I am using rum cards for ports I have the storage of 100k+ at, the general trade report tab says that me storing rum at say Kanoni is making me lose money, but when I use the rum card, I gain more money than I lost. This makes the general trade report tab give false knowledge about my trade profit overall.
Ex: I have a rum card, and at Kanoni I have a warehouse with 100k storage. The trade route I use is Kanoni (store) - Baramas, and my general trade report tab says I have lost 1million every day, but I have used a rum card and made 1million everyday instead.
So instead of the general trade report recording my trade route profit at Kanoni - Baramas, it doesn't. In other words, any use of storage at trade routes will not be recorded at the general trade route tab.