double messages

I am receiving a fairly high percentages of double messages recently--in the past 2 weeks or so--from the same sender, separated by anywhere from 2 to 6 minutes or so. I would guess about 5 percent, without actually counting. Maybe higher, certainly not less. Can something be wrong, and if so, can something be done to fix it? (I know that the list is not the place to post this, but I don't know where else, and surely SuSErs read the list.) --doug