The multi-dimensional Langevin approach is among the most powerful approach for understanding nuclear dynamics, in general, and fission, in particular. This work is devoted to a meticulous study of some limitations of current Langevin models. Evidence for the occurrence of potential spurious features is demonstrated. These are the results of a puzzling interplay involving the transport coefficients which govern the dynamics, on the one hand, and the modelling of nuclear shapes and scission, on the other hand. We reveal the conditions under which, and the mechanism by which, the result can be biased by practical aspects of the implementation of the theory. The implications of this study for the interpretation of experimental data are also discussed. As critical and cautious analysis of the predictions is recommended, and we comment on a strategy for identifying possible bias.