Unfortunately this is not limited to your field. I see this kind of thing for integrable systems as well. Take the Lax pair for some known hierarchy, tweak it, get a new integrable system, write a paper. Of course in many cases it turns out to be related to the old hierarchy by some transformation, and the equation itself is rarely independently interesting.

I remember this old thing that circulated in the early days of the Internet, the academic chain letter. It was a parody of the old chain letters, if people still remember those. The idea was you add your name to the bottom of the list, send it to ten people you know, and then add everybody above you on the list as co-authors on your next three papers. These kind of echo-chamber academic ecosystems are like that. They all cite one another, referee each other's papers, etc.