Oh, forgot to add ... like a dummy, I didn't wash, rinse, boil the raisins ... just opened the box and dumped them in.
In hindsight, this was probably the wrong way to add them.
I contacted Sunmaid directly and asked if they put wax or vegetable oil to their Zante Currants during processing and received the predictable "No". However, looking online (again) I find that manufacturers often add wax and/or veggie oil to the raisins to keep them from clumping.
If I add again, I will wash ... and like others, maybe even boil first ... then rinse, then add.
I do think I'll be able to float the oil off the wine ... it's really just a little bit ... but anytime I see something floating on top of my wine, I panic.