I have never heard of that particular scenario. According to Planned Parenthood, less than 1 out of 100 women will get pregnant each year if they always take the pill each day as directed. The pill may be slightly less effective for women who are very overweight. Certain medications, such as the antibiotic called rifampin and oral medications to treat a yeast infection, can make the pill less effective. Vomiting and diarrhea can keep the pill from working.
There is always a chance for pregnancy when sperm comes in contact with the vagina, regardless of how it got there.