According to an FRC Inspection Checklist
the cRIO must be configured for battery voltage monitoring on Analong Input 8 of cRIO slot 1.
When we connected a jumper to that AI the DS didn’t write the battery voltage,
However when we connected the jumper to the AI-like connection next to the AI8 it works.
Is this legal?
Your second configuration is not only legal, it is the only correct way to do it.