He's always had a high K rate, and a "hole in his swing," so he's probably been trying to fix it for a long time.
He also faced failure in 2015 & 2016- a long stretch:
.682 in 471 PAs at Greenville.
.684 in 339 PAs at Greenville & Salem
With Moreland, Pearce & JD hurt, Chavis will get a chance to fix his swing at the big league level. It's not ideal, but it is what it is.
He may get sent down at some point. We'll see, if he can snap out of it soon.