I heard about this on an older thread and checked myself with both Coinbase Pro account and also Bittrex and it appears to be the case.
Comparing the Market data with Cointracker data, and sure enough the amount of coin received and the amount spent minus the fee is correct, and is the fee, but the cost basis skips adding the fee in. See attached example.
The cost basis should be 2500 dollars. I spent 2500. There was a 12.44 fee. The math for the 2500-12.44 (2487.56) times the amount of coin received (0.04534918) does add up correctly to the price I got in at for btc (54,853.52) so this is correct. However, shouldn’t the cost basis be 2500 even?
This is a bit of a bummer to discover only after I have submitted my taxes but better late than never…