Talk:ISO to USB
Troubleshooting would usually start with ruling out a physical layer or hardware issue by trying a USB stick other than the PNY, but it looks like the default ubuntu USB creator has a number of critical bugs on its tracker page mainly related to differing versions of linux on the system and the ISO/USB installer.
https://www.pendrivelinux.com/ has a USB installation Tutorials section below main page middle with a right tab titled USB-Creators with a list of tools for making bootable installers.
https://www.pendrivelinux.com/liveusb-install-live-usb-creator/ Looks like a good alternative to try. The tools needed will depend on whether the goal is to create a small USB install stick or one that can be used to run the Full OSE Linux Live from a large fast memory device.