BP bought out BPMP (a Partnership/llc) The sale of BPMP is showing in my 1099-b download as short term gain. Should I delete that entry and add it in the K1?

You need to enter the sale by reporting the Form 1099-B in the investment income section. If you think the gain reported is wrong, you will see an option to change the cost basis reported to modify or eliminate the gain reported. This is because the IRS will want to match the income reported on the 1099-B form to your investment sales reported on schedule D and form 8949. 

It is not recommended to modify entries reported on a K-1 form when you enter it in TurboTax. Doing so could void your TurboTax guarantee. If you do modify the entry to add income, however, it is likely you will not draw a lot of scrutiny from the IRS if it results in an increase in your tax.

BPMP should have provided a supplemental schedule for reporting the sale. I can with 99.99999999999999% accuracy say the broker is not reporting the correct tax basis. that you need to get from that supplemental schedule.

additional info for reporting the sale of a PTP/MLP

MLP reporting k-1 and 8949

Please follow these instructions. Incorrect entries can result in entering the sale twice or otherwise incorrectly. Also see the sales schedule that was included with the k-1

Enter the k-1 info
Check the PTP box
If total disposition proceed as follows:
Check final K-1 (s/b marked on actual k-1)
Check sold or otherwise disposed of entire interest
Use QuickZoom to get to the following section (maybe only available on desktop versions) but in online versions you should eventually get to a screen to enter this info.

On the k-1 disposition section for sales price use the ordinary income (sometimes you’ll see a column with the “751” or the words “Gain subject to recapture as ordinary income”. This info comes from the supplemental sales schedule that should have been provided.
Cost is zero
Ordinary income is the sales price.
This info flows to form 4797 line 10 and is taxed as ordinary income.

Now for the 8949.
The broker’s form is probably coded as B or E – sales proceeds but not cost basis reported to the IRS. This is because the broker does not track the tax basis. It used what you paid originally which is not correct.

The correct tax basis is:
What you paid originally, should be the same as what is on 1099-B as cost,
Then there is a column on the sales schedule that says cumulative adjustment to basis. If it’s positive add it to the original cost. If it’s negative subtract the amount.
Finally add the amount of ordinary income reported above.
The result is your corrected cost basis for form 8949.

Some other things. Look at lines 20Z1. That number should be added to the ordinary income above for reporting the 199A (qualified business income from the PTP). You don’t have to enter this but then you lose out on a tax deduction = 20% of this amount.