UMLR — Conflicting constraints

One of the constraints on objectFlows in 15.7.22.6 is

compatible_types
ObjectNodes connected by an ObjectFlow, with optionally intervening ControlNodes, must have compatible types. In particular, the downstream ObjectNode type must be the same or a supertype of the upstream ObjectNode type.

It is unclear how this has to be interpreted in the case of two objectNodes with a decisionNode in between. More specifically,

Imagine a decisionNode with 2 incoming objectFlows:

• 1 objectFlow, whose target is the decisionNode and whose source is an outputPin of type A
• 1 objectFlow, whose target is the decisionNode, and whose source is an outputPin of type Boolean. This objectFlow is tagged as the decisionInputFlow of the decisionNode

The decisionNode also has 2 outgoing objectFlows, guarded by [verdict] and [!verdict] and targeting to (two) inputPins of type A

Whereas the latter model snippet seems to be a valid model according to the documentation on DecisionNode, the 'compatible_types' constraint does not hold for the connection between the outputpin of type Boolean and any inputPin of type A, since A is not a supertype of boolean.