Looking for advice on property boundary issue

[Dan L.]

Hi everyone, 

I recently bought a duplex in Seattle and was planning on renting out half and live in the other half. This place was previously a building on a lot that was subdivided, and a set of townhomes was built in the backyard by the seller. 

One thing I missed during the buying process was the fence did not accurately reflect the property boundaries and it turns out the neighbor owns some of the property enclosed within my fence (area in question in red, fence in green). On top of this, the property the neighbor owns overlaps my outdoor stairs that were already there. The issue was never disclosed in the form 17 question about boundary issues, and there is a covenant about encroachments when I asked my agent and title co (attached).

Could this cause trouble in the future? Is there anything I can do about this from a legal standpoint, to either fix the boundary or get some refund? Should I lawyer up?

Thanks for the help!