Schedule K-1 box11 "contracts and straddles"

Hope to get advice for ETF stock "USO" schedule K-1 box 11, really appreciated if anyone can help.

 

When I see my uso schedule K-1, the box 11 shows “contracts and straddle” income of about $8000. I don't know what it is. I made several USO  buys and sales (7000sh) in 2019, total gain of $1,300 (if add 2018 wash sale loss, the 2019 total should be a loss), however I am facing a big tax on this $8,000 "contracts and straddles income". I don't see any of this on my 1099-B, I have no idea where the money came from and went to. 

 

I am wondering if there is an error in the box 11. I consulted my tax advisor, he also said it seemed too high and told me to call the USO fund. When I called the call center, they told me they could only verify the “ownership schedule”, not specific K-1 numbers. So is this the normal USO tax consequence? I mean  don't see money but need to pay tax? I am very frustrated with the USO K-1.   Thank you very much if you can offer an advice.