When executing a trade on Coinbase Advanced Trading where the order has multiple fills at the same timestamp, we are only importing one fill currently. The remaining fill transactions are not imported because we are identifying them as duplicates.
This results in incorrect asset balances/cost basis/proceeds/gains/etc. in CoinTracker.
Our engineering team is investigating this as a priority issue.
If wish, you can add the missing transactions manually to make your data more accurate. Please be aware that when we roll out a fix and start adding all fills through the sync, the manual transactions will need to be removed.