In Sun/Moon, Zygarde can have either Aura Break or Power Construct. Can a Zygarde formed from the Zygarde cube have Power Construct? Is it random? Or is there another way to get Power Construct?
It depends on how many Zygarde Cells you collect; if you collect 10 or 50, then Zygarde will be in 10%/50% Forms, albeit with Aura Break. Only if you collect and combine all 100 cells do you get a Complete Zygarde w/ Power Construct.
Hope I was able to help!