As long as you don’t test it you are in a quantum state, the same as for the Schrödinger’s cat. Your code is either buggy or is not.
Hence, bugs are in fact triggered by users.
I tried to solve some of the last Advent of Code enigmas with LispE, and I discovered a plethora of problems, which I didn’t think would erupt after so many years of tests.
This just seems like an epistemic issue. The code either is or is not buggy regardless of whether anyone looks at it, that question does have an answer. Whether you do (or can) know whether it is buggy is just a different question.