The Decoys seem to not appear when dodging the first attack in a combo or single strikes such as unblockables.
#Chamariz Decoys Not Always Appearing on Dodge.
plucky glacier
plucky glacier
Update: they also seem to be delayed as after a clear attack dodged they don't make the decoy but then when I dodged after the fight is done it spawns decoys. If this is the intent it would be helpful to change the abilities description as it currently seems to indicate that the decoy triggers on a successfully dodge attack.