Box around drop shadow on prints

rasterize the whole design...or you can try setting your rendering intents to be the same for raster and vector data - this is ultimately caused by 'spot color over transparency'

 

That's an Illustrator glitch. As mentioned - you need to rasterize anything that uses the filters in Illy. Versaworks doesn't like the way Adobe defines transparent areas of an image.

 

Not 100% sure this was the right way to fix this but when you do flatten and rasterize there is a box with "Preserve Spot Colors".
Do not have this checked. I was having the same issues and this fixed it for me.

May create issues for cut files but for just printing it was ok.

 

Are you using Versaworks as your RIP, and if so, are you using Max Impact for your color management settings? If you're using Max Impact that could be doing it, try it with Prepress US.

 

I have noticed that graphic agencies seem to use this method. Personally, your issue isn't something I run into all that often, but I think it may have to do with your ICC profiles?...