Should the cost basis and gain/loss be in the hundreds of thousands and millions for my crypto trades? This seems incorrect but came from the raw CSV data

I've just spent 4 hours trying to figure this out after encountering the exact same issue.

My actual gains/losses are around $3,000 verified by both Coinbase and the CSV data.

However when imported from Coinbase  (via API and CSV both) it is telling me I have a one loss of $1,352,401.39 on a single transaction and another loss of $16,842.94. In reality the loss on this transaction is less than $1000. There is absolutely no way I'm going to file with those kind of numbers.

I think something is broken?

Depending on the number of transactions you have imported, one solution would be to look at any that have a zero cost or sales amount and enter 1 in both cost and sales boxes.  If both are showing zero you can delete the transaction with the trash can icon.

If some have sales amounts but no cost basis and some have basis with no sales amounts, keep track of them, add all the sales amounts together, and all the cost basis amounts together, and combine them into a single transaction outside of the import feature.  After this, delete the entries you combined.  This has worked in the past.

Another method would be to request if you do not already have one, Form 8949 from the Crypto agency you traded with. Delete all imported transactions, and enter the totals as a single transaction as shown on the 8949.  

You may want to include a pdf file of the 8949 for additional verification when you file your return.

The IRS is concerned that you are properly reporting your total capital transactions with their associated cost basis and while individual transactions are important, the totals are the most important.

@cbittle1174