Several minutes' searching failed to find a single real-world example of this happening with open source software specifically, and I don't recall hearing about any such case either.

All of the liabilities I found for open source software involved intellectual property cases.

Are you aware of any cases where this has actually happened? Because, if not, it sounds more like the standard boilerplate disclaimer that lawyers tell you to include just in case anyone ever does try such a thing, rather than a protection against a thing that has actually happened.