Rufus says my USB drive has bad blocks, how do I fix it?
The flash drive is failing and should be replaced.
The most likely cause of this issue is flash memory that is wearing out. Flash memory has limited endurance and USB flash drives tend to use lower-grade NAND which has lower endurance than the types found in SSDs. See: Can a USB thumb drive "wear out"?
This problem cannot be resolved by the end user. The drive should be replaced as continued use can eventually result in data loss.