Damages to the seam of the zipper fabric always pose the risk of widening and leading to the zipper chain getting loose.
For very small damages to the seam or the fabric we recommend to avoid pulling on the strings. You can try to secure the loose ends by pushing them back inside the fabric with a needle.
Larger damages to the seam or the fabric are unfortunately not repairable and would require a complete exchange of the entire zipper which is not economically viable for most suitcases.