I'm guessing we see Folty tighten up his control closer to his career rates, and we see Newk's 0.58 HR/9 in 2018 regress a little closer to 1.
Folty has since improved his BB rate to 4.04, with a mark of 2.9 since this quoted post.
Newk now has a HR/9 of 0.68 (8.3% HR/FB), with a mark of 0.8 (9.1% HR/FB) since this quoted post. I suspect there is still a bit of room for regression.
Newk has spent 7 months at the MLB level, compiling 35 starts (just a bit more than a full season). Here are his HR/FB rates as well as his wOBA each month of his MLB career:
June 2017 - 4.8%, .242 wOBA
July 2017 - 16.7%, .388 wOBA
Aug 2017 - 17.2%, .373 wOBA
Sept 2017 - 0.0%, .308 wOBA
April 2018 - 12.5%, .320 wOBA
May 2018 - 0.0%, .218 wOBA
June 2018 - 14.2%, .294 wOBA
Notice how strongly his wOBA correlates to his luck on HR/FB?
Now, after seeing this same phenomenon in action with MAdams, Albies and Newk, have we learned anything about HR/FB rates yet? How many more times are folks going to argue when we point out that success based on unsustainable BABIP, HR/FB or LOB rates is unlikely to continue?