What is wrong with the blind rivets?

There may be two reasons for the inequity:

1. The blind rivet specification is too long, which does not match the riveting thickness.

2. The rivet gun and the plate have not been placed in a horizontal position, and the rivet has been pulled, causing the rivet to be crooked after pulling!

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