Object very close to the floor detected as floor

[pepperig]

Hi all,
I am trying to use the understanding feature with hololens. I need to recognize a plane on the floor with its heigh below 1 cm. The object is identified as Floor and so I cannot perform any queries. Instead if I try with a higher object it is detected ad FloorLike and it works fine.
I tried to play with some number inside the TopologyAnalyzer_W::IsFloor_V3 methods but no result.
Where should I look?
Thanks