When you claim a home office, you are required to take depreciation based on the square foot percentage of your home claimed as such. (This changed in 2013, covered below.) When you sell the property you are required to recapture and pay taxes on all depreciation taken. Even if you qualify for the "2 of last 5" capital gains tax exclusion, the recaptured depreciation is still taxable and is added to your AGI in the year you sell the property. So if you claimed a home office, or any other business use of your home (such as renting out a room) it's common for the 1099-S to be issued to the seller.
Beginning in the 2013 tax year, businesses claiming a home office had/have the option of taking a "standard deduction" of $5 per square foot of space claimed for a home office, up to a maximum of 300 square feet. With this option, no other office expenses can be claimed. Additionally, no depreciation recapture is required. This is referred to as the "Simplified Option" for the home office deduction. For greater detail and a comparison between the two options, see https://www.irs.gov/businesses/small-businesses-self-employed/simplified-option-for-home-office-dedu...
