I don't know if others have this effect but if I manage to change the morning routine IE if on a flight with changed time zones, my 'normal' IBS-D goes away.
Problem is then that I might struggle to move my bowels for a day or two but eventually produce an actual solid movement.
Also noted that If I move my bowels in the late evening (rarely) it is a totally different experience and smells very different, sorry if that is too graphic. It is just such a mystery.