The model is conditioned / pretrained to use a particular version of a library. The model doesn’t know why — it was just taught to use that version. To the model, it is just some insignificant detail in the grand scheme of things. It’s just like how a model would intuitively favour using English without explicit instructions — it’s not trying to sabotage other cultures, it’s just what it does.
But that would happen with literally any model without grounding and is more of a quality/competence issue, not what's being discussed. It'd be a bit of stretch to conclude open models are no more auditable than closed models based on that possibility alone.
Also, in that case, there would likely be activations indicating that it is favoring a specific version. If that's an insecure version, sure that'd be suspicious... but again, you're only going to be able to verify that's what's happening in an open model.
Maybe you can illustrate a realistic scenario in which that would be a problem, otherwise I don't really understand what your point is in this context.