I've experienced a similar issue recently. I don't know if all "corn syrup" is the same. Mine is branded Golden Barrel - Light Corn Syrup from Amazon. When using the calculations found in this forum for the correct amount of "corn syrup", I have had opalescence issues in some of my batches and when stored in transparent (1 gallon plastic jugs) and left in fluorescent light for a couple weeks, it turns turbid. Its obvious there are unreduced silver ions that are agglomerating.
I made an experimental batch yesterday that I purposely added an excessive amount of corn syrup to see if I get a different result. The answer is a resounding yes. Of course I won't know for sure until I let it set in light, but there is no opalescence of any kind that I can see. Based on my prior experience, I'm convinced all the silver ions have been reduced to nano-particles in this batch.
My batch was 4L water, 15ml undiluted "Golden Barrel" corn syrup, 4g beef gelatin bloomed in cold DW then warmed, stirred and added. Electrolyte solution added to bring the voltage down to 11 volts. Its worth noting that the "Vital Proteins" brand beef gelatin that I bought from Amazon does raise the conductivity of DW. Its the only brand I have tried so I don't know if this is common among other brands or what (??)
Current limited to 20mA, 5 hours process time (processing for 100ppm), Heat stirred with average temperature 72C (would prefer it was a bit warmer but this is what I documented)
Photo attached of 100mL sample calibrated to 20ppm (20mL 100ppm with 80mL DW added)