Nothing wrong at all. Some features you can bolt on, and some features fundamentally change how a system works requiring changes at many different levels of the stack. Happens all the time.
It happens in poorly factored codebases. If you find it happening that's a sign you need to refactor. If you find it happening repeatedly in the same codebase that means you failed to refactor properly the first time.
It happens in poorly factored codebases. If you find it happening that's a sign you need to refactor. If you find it happening repeatedly in the same codebase that means you failed to refactor properly the first time.