I'm guessing just a casting defect for that run. I think I have a late 2014 and the two in the link were both 2015's.What could have caused that, I wonder? We now have two cases, one from you and one from the link posted.
I'm more inclined to think it's a manufacturing defect because of the Reddit post I found. Same exact crack as mine, on 2 other cars.I would think the mostly cause would be overheating/lack of oiling. It’s rare to see on the 3rd gens especially 14-16 models but on the newer models 17- the heads do have a manufacturing defect in some instances where a crack will form by the #2 and 3 exhaust ports. This would be the first case I’ve seen of an early model but we actually had a 6 come in that blew a hole straight through the block. The 6 was a 15 with about 150k I believe and the guy who drove it didn’t really take care of it.