A question of pits and stomachs

Since around the year 2000, confirmed by Ngrams, the common phrase "I felt (dread etc) in the pit of my stomach" has become somewhat corrupted to "I had (or felt) a pit in my stomach". I’ve seen it several times recently in internet posts and popular fiction.

I doubt there’s a ‘patient zero’ to be found, but I’m curious what might explain why this has become increasingly popular, when before 2000 it was virtually non-existent.

I hope this isn’t seen as opinion-based — I’m looking for a scholarly, or at least informed, reason why this might have arisen.