The dispersive threshold voltage drift in silicon carbide metal-oxide-semiconductor field-effect transistors (MOSFETs) severely impacts their reliability in applications. The Tesla Model 3 recall incident highlighted that the "rear motor inverter power semiconductor components" might have "minor manufacturing variations," which could lead to inverter failure over time, resulting in the inverter"s inability to control current properly. This paper conducts a systematic study on the recall event from two perspectives: device intrinsic differences and circuit loop parameter variations. The intrinsic differences in devices may cause the threshold voltage dispersion to increase with prolonged stress time, thereby exacerbating current sharing issues. Additionally, variations in parasitic inductance in the drive and main circuits can also worsen current sharing. The research demonstrates that both device intrinsic differences and circuit loop parameter variations can influence the threshold voltage drift dispersion, leading to deteriorated current sharing and ultimately causing system failures.