How did you make the cell builder? Was there brood in the cell builder? If so, then wait at least a couple of days to see which cells they are making into queen cells. Remove them and then perhaps wait a day before you introduce your graphs.
Do you leave the brood in there after you put your frame of grafts in? Strange how experiences are so different. When I made up a cell builder (with all capped brood) the day before adding graphs I got 40 cells (from eggs scattered over the frames that I didn't notice). Just none on the cell bar. Every frame had multiple queen cells. One frame had 13.I do NOT remove open brood. IN fact I move some open brood up to the top box next to the cups that are in there to be polished (grafting frame), then next day when you graft and put the cups in with the grafted larva there will be lots of nurse bees close by ready to take over.