It's pretty common for the 1099-Bs to require you to make adjustments. So if the Vanguard statement is wrong or incomplete, you can adjust.
The way you do this is via the Form 8949. As a compulsive linker, here's address for the actual form instructions:
https://www.irs.gov/pub/irs-pdf/i8949.pdfYou want to make sure you have your facts straight and your accounting right on this. I would assume those adjustments bump your audit risk.