In[113]:= a = Rectangle[{0, 0}, {1, 1}, RoundingRadius -> 0.5];
In[114]:= ToNumericalRegion[a]
Out[114]= NumericalRegion[None, {{0., 1.}, {0., 1.}}]
The bug appears only with Rounding and only if I do not combine this rectangle with other shapes,e.g. by RegionUnion If I combine with other shapes, there is no nasty bug, but rounding does not appear if I make a mesh region out of it.
