StarkEffect:

However, if loaded in another notebook, the results of inference resemble those of an untrained model.


Did you apply the same preprocessing the the samples in both notebooks?
If so, did you call model.eval() to disable dropout and to use the running stats in batchnorm layers?
Once this is done, check the model output for a static input (e.g. torch.ones) and calculate the abs().max() error.