It is worth pointing out that damnatio memoriae is not actually an ancient phrase, or even really an ancient concept. There are cases of emperors having public monuments defaced but it wasn't really the official, organized, act of rewriting history that it is sometimes portrayed as in popular imagination. Think more pulling down Saddam Hussein's statues in Iraq or changing the street names in Germany after the second world war than something out of 1984.

In this case this is probably less any deliberate act of disrespect and more that our sources for the so-called Third Century Crisis are somewhat poor, and Dacia is a somewhat poorly understood region of the empire.