How do you know that was a React issue and not a memory leak, or an error in your own code perhaps?
This smells of a memory leak, particularly if you forgot to add a dependency to a hook for example, but there is plenty of non react related code that could go wrong with drag and drop interfaces too
Not using any hooks, it's simple old-school react started from create-react-app, then converted over to Preact, and then updated to use latest webpack and all libs updated to latest versions, so this project has gone through many changes and I have no doubt if I started it new today from the ground up things would be different. I think the problem was with the drag-drop library, react-dnd I think. But the point is that switching from DOM to a canvas solution fixed all the problems I was having.
This smells of a memory leak, particularly if you forgot to add a dependency to a hook for example, but there is plenty of non react related code that could go wrong with drag and drop interfaces too