This comment is not precisely about this paper which is an interesting and important study by itself. This comment is about interrelation of this paper and the paper A. Khrennikov, Basieva, I., Dzhafarov, E.N., Busemeyer, J.R. (2014). Quantum Models for Psychological Measurements : An Unsolved Problem. PLoS ONE. 9. Article ID: e110909.
where the ABA problem was formulated the first time.

In fact, the question asked in 2014-paper was whether all possible mental experiments can be described by the quantum observables. We started with Hermitian observables and then considered POVMs. As was emphasized by Ehtibar Dzhafarov, to show that neither of them can be applicable to describe ALL POSSIBLE mental observations, it is enough to find JUST ONE experimental situation as a counter-example. The recent paper of Busemeyer and Wang does not eliminate the claim: “there is a nonempty set of questions A and B such that if the second A in ABA will evoke the same response as the first one.”