Greenback will mark some transactions synced from Amazon Seller as "open". Open transactions are not ready to export to an accounting system. Trust us, this is not a bug, this is an important feature for accurate accounting.
Each Amazon marketplace (e.g. United States, Canada, United Kingdom, etc.) has a default currency they transact in for orders with customers and fees they charge you. For example, if you participate in the Amazon.com United States marketplace, all orders and fees will be in USD (United States Dollars). If you participate in the Amazon.ca marketplace, all orders and fees will be in CAD (Canadian Dollars).
As a convenience to merchants, Amazon allows you to get payouts (settlements) in a currency that differs from the marketplace. While convenient for the merchant, it makes the accounting under-the-hood a little less flexible while syncing data. When a currency conversion will be involved for a merchant on a specific marketplace, Amazon only shares the final exchange rate when a settlement (payout) occurs. Until that final exchange rate is known, Greenback cannot set an exchange rate on transactions in the current "open" settlement period. Therefore, Greenback sets the status of these transactions to "open" to protect you from exporting them until they are completely finalized.
Once the settlement occurs, Greenback will detect this occurred on a future account sync, and update all "open" transactions and include the final exchange rate. These transactions will now be ready for export to your accounting system. Since you setup Amazon Seller to settle these in a different currency from the marketplace, it's probably safe to assume this is the base (home) currency of your accounting system. Since Greenback waited until the final exchange rate was known, once they are closed, they will have the precise exchange rate Amazon used, which lets you sleep well at night knowing your Amazon Seller data is 100% accurate.
Please be aware that from the time Amazon "settles" your transactions, there can be a delay of a few hours or more before the settlement data is available for Greenback.
Most merchants get settled by Amazon every 2-14 days depending on your volume. If you login to your Amazon Seller dashboard, you can check which settlement is currently open. If a currency exchange is involved in your settlement for that marketplace, they will close on Greenback sometime after Amazon reports that time period as closed.