BABIP of .297 so not even really unlucky, just a lot more weak contact.
It's also not his K rate, either. 22% isn't a killer. He's gone from a .232 ISO to .082. Some of his numbers, like hard hit rate, don't show a decline. A bit less loft, a bit lower average velocity on contact, combined, even his his x numbers on BA and SLG are just a tick down. There's some luck in it (xBA is .030 better than his batting average, which ripples through to his SLG).
I'd say a chunk is return to expectations, some is worse contact, and a chunk is bad luck still. Maybe 50% - 20%- 30%?