Actually, by the text, we don't know if artificers are dual stat casters or not, since it never tells us what ability their saves are based on. For all we know, it could be Wis, or even Str or something. I'd noticed this problem before, with the Disable Construct infusion (basically, Harm vs. constructs), which will always offer a save.Quoth PallentisLunam
EDIT: Forget that last part, artificers aren't dual stat casters don't know where I got that idea
However, this was fixed in the errata. Artificer infusions do indeed have a save DC based on Int.