I don't recommend leaving the loose ties, because they will fall out sooner or later. I would pull them out and put in new ties. I don't know how you are doing your knots, but granny knots will not hold. I work with different charity groups, and occasionally we get a quilt in where all I have to do is pull on the end of a tie, and it comes right out. Not good. Those quilts have to be retied.
Don't give up!
Dayle