I would think that this would be the case with any sort of fruit extract. You're adding additional fermentables (more present in some fruits than others based on different sugar contents) so it's best to give the yeasties a chance to turn those into EtOH before bottling.
I've never brewed with fruit before so take this with a grain of salt, but I've always heard to add the fruit or fruit extract to a secondary, rack the beer onto the secondary, wait 1-2 weeks, and then bottle or keg. The secondary will give the yeast time to eat up the sugars from the fruit. No idea on differences between real fruit and extract. I can't imagine HFCS hurting anything - just more food for the yeast.