Discrepancy in UpSetR, Eulerr and my data

Question

The values shown in the diagrams of my venn or UpSetR plot is different than what my data has.

Hi, I would really appreciate help with the following:

I have 10 sets of vector and just with an example, I have one vector (let's say x) with a total of 972 items.

However when I plot the data with other gene sets with UpSetR or Eulerr's Venn using the codes:

upset(fromList(SC), 
      empty.intersections = "on",
      nsets = 10,
      order.by = "freq")

OR

venn <- euler(SC)
plot(venn, counts = TRUE, quantities = TRUE,
     labels = list(fontsize = 7))

and following, I summed up my item values for x showed in the diagrams, but I do not get 972. I would get 947.

So I check with just performing Venn diagram with only 2 sets and it was completely fine.

May I please ask what may be the reason for this "error" when I plot a venn with large number of sets please?