Keeping UERs separate makes a lot of sense to me. This is all much less interesting if they're never fixed.
Not only is this error apparently on the SPs, parallels, and inserts (like the 1984 anniversary set), it appears this has carried over to 2019 Topps Heritage as well. I only checked a few cards, but it appears this is only for the players who have flagship Series 1 cards. For example, Ross Stripling and Hyun-Jin Ryu's cards are correct. Of course it's only ERA affected here, not WHIP.
(Millions of kids are going to grow up thinking Kershaw's career ERA is merely the outstanding 2.59, not the otherworldly 2.39 it actually is. How will they ever find out the truth?)
Here's the list of the ones I found in Series 1, if anyone is interested in working on other sets.
2 Tyler Anderson
5 Chase Anderson
10 Clayton Kershaw
30 Josh Hader
40 Jon Lester
73 Jon Gray
74 Chad Bettis
81 Wade Davis
105 Jose Quintana
106 Adam Ottavino
122 Zach Davies
129 Kenley Jansen
142 Pedro Strop
171 Kyle Hendricks
181 Antonio Senzatela
267 Ross Stripling
283 Rich Hill