When spawning an instance of a blueprint using an archetype that is not a class default object, child components will be attached to the template component instead of the instance.
1. Download [Link Removed]
2. Unzip it in UE4\QAGame\Source folder (click yes if it asks to overwrite existing files)
3. Build QAGame Editor
4. Create a new blueprint in the root content folder (QAGame\Content) with TestPawn as its parent class, name it TestPawnBP (name and location are important!)
5. Start PIE
6. Type TestTestPawn in the console
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-15502 in the post.