In the Floor Plan Cut Plane Settings Dialog, try to set the Show Down To value to a lower value, such as -4' or something.
What is your Story Height on Story 1? Because the value needed will depend on that.
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AMD Ryzen9 5900X CPU, 64 GB RAM 3600 MHz, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), Windows 10 PRO ENG, Ac20-Ac27