An ActivityPartition cannot be contained in both an Activity and an ActivityPartition.
The involved ActivityPartition is contained by both another ActivityPartition (through the SuperPartition relationship) and an Activity (through the InActivity relationship), but these relationships should be exclusive of one another.
This rule is usually triggered by a malfunctioning module (or macro). Please contact the module authors so they may fix it.
The problem can be fixed manually by moving the involved ActivityPartition so that it is directly contained by the Activity and then move it back to its place.