Windchill Project Plan: Critical Chain gets redistributed when parallel non-critical tasks are completed

Hi,

I am facing an issue with Windchill Project Plans / Critical Chain scheduling.

I have a project schedule with the following structure:

Parent Activity
├── Parallel Activity A
├── Parallel Activity B
├── Parallel Activity C
└── Main Activity → Activity → Activity → Activity → ...

The three parallel activities are intentionally independent from the main activity. They have the same predecessor (the parent activity), but there is no dependency between the parallel activities and the main activity.

The intended behavior is:

• The parallel activities should remain independent/non-critical.
• The main activity chain should remain the project's critical chain.
• Completing any of the parallel non-critical activities should not redistribute, shift, or recalculate the existing critical chain.
• The project structure/dependencies should remain unchanged after completing those activities.

Issue

When one of the parallel non-critical activities is completed, Windchill recalculates the schedule and the critical chain changes/distributes to a different path.

This happens even though:

• The parallel activities have no predecessor/successor relationship with the main critical-chain activities.
• The parallel activities are intended to be non-critical.
• The main chain is intended to remain the controlling chain for the project.

Expected behavior

I would like to maintain the following logic:

Parent
├── Independent Non-Critical Activity A
├── Independent Non-Critical Activity B
├── Independent Non-Critical Activity C
└── Main Critical Chain
     ↓
     Activity
     ↓
     Activity
     ↓
     Activity

Completing A, B, or C should not cause the critical chain to be redistributed.

Windchill version: 13.0

Thanks in advance for any guidance.