In my experience in most cases, this happens because the Point Cloud is out of the vertical range of the Story.
I would create a Section that cuts through the Point Cloud and check exactly where it is located vertically. Maybe it is much higher or lower than the Story's vertical range. So bring it into the vertical range of your Story.
The Floor Plan Cut Plane settings may also influence whether/how much the Point Cloud is visible in the Floor Plan. You can check that as well.
....................................................................................................
Get Archicad Tips at https://twitter.com/laszlonagy
AMD Ryzen 1700X CPU, 48 GB RAM, Nvidia GTX 1060 6GB, 500 GB NVMe SSD
2x28" (2560x1440), WIN10 PRO ENG, AC20-AC25
Loving Archicad since 1995