He aha ka manaʻo o ka jumper rivet makapō?

Poʻo lele rivet makapō: no ka mea, ʻaʻole e kāʻei ka rivet i ke poʻo kui, e hana ia i ke poʻo lele rivet.

https://www.yukerivet.com/news/the-core-of-the-blind-rivet-is-not-completely-pulled-out-what-is-the-reason-for-the-fracture/