Susan Minot and grammar

I'm mystified by the fact that Minot regularly uses the word "lay" as the past tense of the transitive, present-tense verb "lay". Example from Don't Be a Stranger p. 71): "She lay her hand on his chest." It's not her only grammatical error, but it's the most prominent and most repeated. She knows the word "laid" and is not afraid to use it, as it appears 11 times in the book, but she frequently writes "lay" in its place.

Minot is not alone in this. I've noticed other contemporary writers making the same mistake. But Minot seems to do it more regularly than anyone else.

Why don't editors catch these blatant errors?