It looks like one of the knots slipped? I hope you are better at knots than I am, because for me it took longer to make the second knot exactly like the first one than to actually make the earrings or the bracelet... Maybe I should have used glue?
The knots do slip a bit, but a quick tug on the chains and the knot is back to where it needs to be, so it's not a problem.
I don't know how well glue would work. I think it would be difficult to make the glue fairly invisible. Maybe a small amount would stop the slipping? It's really not a problem though - the earrings are fabulous