Does your spindle have the GX16-3 connector ? Have a look at the PLUG as well and see if there are any burn marks on the female pins they are split as well. I t could be the cable from the VFD has a break somewhere and that has shorted back to the spindle.

E14 "The inverter is protected by the detection ofground faults between the inverter output and themotor during powerup tests. This feature protectsthe inverter, and does not protect humans."

Sounds likely that there is a break in the cable which has flashed at the GX16 connection causing the split in the pin to draw together.