My credit card transactions are only syncing until August 2018. I'm not seeing anything for Sept, Oct, Nov, Dec 2018 and I have many transactions that occurred?
Was there a new credit card number issued after August 2018? You will have to re-connect credit cards when a new card number is issued. You should disconnect and reconnect your credit card. You can download into a csv file any missing transactions and upload them into the bank feed of your credit card.