Model checks fail if a strongly causal component is connected to a weakly causal one
It seems as if initial values of outgoing ports are evaluated regardless
of component causality settings of target component.
Also, the validator expects an initial value for the target input port
which is not present and cannot be defined in the UI.
Currently, this can only be solved by opening the project file in an editor and adding the missing value.
(from redmine: issue id 2739, created on 2016-11-21, closed on 2017-01-30)