Under NVBU 10.x and early NV11 builds, it is possible to create an Advanced Backup Options set without a Target Set for the Secondary Copy section.
The job can be saved without duplicate or datacopy target resulting in phase 2 duplications or datacopies not running or failing without meaningful error messages.
This is a product defect that will be fixed in Bug 30673 as part of a future NV11 Maintenance Release.
The "Use Target Set" field will have the Default Target Set selected and saving the page will only be possible if all fields have values.
To prevent duplications failures, please always ensure all fields under Secondary Copy have a value before saving the set