If you are canning jelly - and using melted paraffin to seal the hot jelly in boiled jars - why do you notice a trail of bubbles coming through the paraffin 15 hours later?

When canning, it is important that you remove all air bubbles before sealing. You can use a knife, spoon, small spatula or any other workable utensil. What you have leaking out is trapped air bubbles. Chances are the seal did not take, so you should refrigerate these immediately.