You can only sell something you possess with the right to sell it; or the distributions could have meant taking possession by rolling/transferring into a different plan. The 1099-R is the distribution document and the 1099-B is the sale. The R establishes basis and any taxable amount because of the distribution, and the B gives gain or loss.

Here:

https://ttlc.intuit.com/community/retirement/discussion/i-received-1099r-and-1099b-for-the-same-esop...