What are you implying here? That someone has created their own LLM therefore they are running a closed weight model on their own computer? Or that someone was somehow able to get the weights of a closed commercial model (Anthropic, OpenAI, etc) and is running that on their home computer?
I mean, yes. Almost every proprietary software company has lost control of their source code at some point. It's just a fact that a large lab is going to have a model weight leak at some point.