We have added an enhancement to our bank transaction import feature in our Accounting Software. When you review your pending transactions that have been automatically imported with Plaid, you will now see a warning when a possible duplicate transaction has already been posted.
This duplicate transaction warning will appear when the pending transaction matches an existing transaction with the same external account (e.g. Savings, Checking, Credit Card), the dollar amounts match, and the date is within seven days of each other. You can still continue and accept or dismiss the pending transaction.
See the help article: Managing Pending Bank Transactions.