Didn’t know about kugis issues, but about as min 3 others have had issues with 8075 motors.
I can confirm that this high pitching noise comes not only on 80xx APS motors. Also the 6384 motors have similar issues at a specific rpm.
It’s not affecting the riding but sound strange.
I got it under control with battle harden the motors.
APS bought or maybe still buy there motors from freerchobby so I wouldn’t expect batter quality from there.
I would rather get a group buy done with leopard 8072 or maytech 8085 motors.
They more expensive but also more reliable.