Thanks for verifying this. With the connection editor, you mapped the Rule Attribute "Eave_Ht" to an Object Attribute named "EaveHeight". This created the following entry in the Layer Attributes of the "Shapes Sample" layer:
attr Eave_Ht = getFloatObjectAttr("EaveHeight")
All Object Attributes of objects in the source layer at the location are getting sampled. In your case the value of the object in the center is returned. The behavior is expected.
To make a direct connection between a Rule Attribute and an Object Attribute, the names must match. Either add an extra (optionally hidden) attribute to your rule
@Hidden
attr EaveHeight = 50
attr Eave_Ht = EaveHeight
or edit the name of the object attribute
Inspector—ArcGIS CityEngine Resources | Documentation