For some reason not all transactions from Coinbase are being imported. When manually adding the missing transaction and merging it with the sent, the cost basis of the sent is lost (set to 0.00).
For instance:
Purchased ABC (valued at $300)
Exchanged ABC (sent) for XYZ (received) for an end value of $292
The XYZ received transaction is not being imported for some reason. So, a manual transaction is made.
When Koinly merges the sent ABC with received XYZ transaction and recalculates, ABC cost basis is set to 0.00 and states that XYZ received is a positive gain of $292.
This issue has disastrous impact on taxes and needs to be fixed.