I just noticed this anomalous branch on my Picea glauca 'Conica'. It is 5 feet tall and about 15 years old. I'm more intrigued than worried but would be very interested to hear what you experts might have to say about it. Perhaps not relevant, but I had low-wattage Christmas lights on it last year for at least 6 weeks, 24-7. Unless I learn otherwise, I'll probably just prune the deviant branch.
It's reverting to Alberta spruce. This is not a rare occurrence with this cultivar. You will have to cut the reversion out.
