ARCore (sometimes) casts multiple shadow from 1 renderable

This what scene normally looks like:

Sometimes after placing renderable on scene there appears 2 shadows of the one object. Why is so?

The issue here is caused by arcore / sceneform detecting two horizontal planes next to each other instead of a single one. Therefore, a shadow is casted on both planes.

The root cause of this is that there might not be enough features points detected, or maybe too much reflection on the surface. By paning the device around, it should force arcore to merge the two planes into one.