It was a great many hours of running a GPU stress test that used 100% of the GPU causing the fans to go full bore.
My guess is coil whine is caused by the parts not fitting together properly meaning that the motor not having enough oomph to move the fans over the extra friction.
A few of my cats over the years have had similar where it weeps constantly as the trapped fur pulls the scab open over and over as they move around and groom themselves until the underlying wound heals and the sticky, gooey mess of fur and scab come off.
It was a great many hours of running a GPU stress test that used 100% of the GPU causing the fans to go full bore.
My guess is coil whine is caused by the parts not fitting together properly meaning that the motor not having enough oomph to move the fans over the extra friction.