When closing the zipper, you need to bring the two sides beside the zipper close together or adjust the fabric's position.
If you pull hard without adjusting it, for example, if the zipper opening angle exceeds 90-120 degrees, the two protrusions will easily pierce the fabric next to the zipper teeth.

Then if you still pull it hard, the zipper tape will tear off, even hurt the zipper teeth.
If the tape is torn, the zipper still can be used carefully.
But if the zipper teeth are hurt, it has no other way but to change the whole zipper.