Hi Vegar,
This is actually not a bug but how mining should be reported.
Cost transactions are a type of disposal so any potential gains should be realized. Here’s an article that explains that in more detail.
Mining transactions are treated as Income. This is not the same as Capital gains and will be reported separately on your reports. If you go to the ‘Tax Reports’ page then you will see the total Income listed.
Most countries require you to report your Income and Capital gains separately. Most countries allow you to deduct the mining costs when reporting the income but some countries don’t allow this which is why we need to import these separately. If your country allows the full deduction of mining expenses then you can deduct those from the total Income when filing your taxes.
Let me know if you have any further questions 
Best regards,
Petur
Thanks for the reply. 
These transactions happen at the same time, so I though it was just how nicehash shows their % fee of the mining. Its really nothing you would ever get to use even if both transaction was over 1 million dollars
Would also be nice to be able to set the api on mining cost to use LIFO so you dont get gains on something you really never really have.
If I find out I can deduct the cost, can I tag the transactions in a easy way to get koinly to show it as deductions?