Can single-sided Power meters cause unnatural Bilateral asymmetric pedaling?
I am unaware of any controlled study that directly addresses your question. 

However, a recently published study by Bini et al. addressed the converse of your question: can the provision of information on bilateral symmetry or asymmetry be used by riders to alter their pedaling dynamics? The Bini et al. study did not address whether riders would benefit from decreased bilateral asymmetry -- it only addressed the limited question of whether it was changeable. The answer appears to be that it can, sometimes. So although your exact question was not addressed, if these results are replicated and verified then a reasonable implication is that if one were to supply the riders with incorrect or misleading information on symmetry the riders might also be able to adjust their pedaling.