From The Collaborative International Dictionary of English v.0.48 :
mistiming \mistiming\ n.
The act or process of assigning something to a time when it
could not have existed or occurred.
Syn: anachronism, misdating.
[WordNet 1.5]
From WordNet (r) 3.0 (2006) :
mistiming
n 1: something located at a time when it could not have existed
or occurred [syn: anachronism, mistiming, misdating]