“…However, contrary to the claims made in some of these papers, the problem of the first passage time moments, and the related issue of finding the asymptotic drift velocity [14], was not solved in the most general case. Indeed, with a few exceptions [15,16,17,18], all the results that have been obtained exclude the cases when one or both of the "±" dynamics have unstable fixed points, and thus do not consider the possibility of crossing unstable fixed points in the long time dynamics. The technical subtleties were first highlighted and discussed in detail in a recent paper [19].…”