Yes I believe Kubota went with Cummins on the larger units.
In 2020, Kubota unveiled its largest tractor to date – the 19,510 lb. / 8550 kg M8. Its big features – power, reliability, comfort and value.
Power comes in the form of a 180 hp (134 kW) or 200 hp (149kW) Cummins B6.7 Performance Series engine. As Cummins’ most popular product, with over 15 million B Series engines built since its introduction, the B6.7 represents next generation engine technology. Its uplift in both power and torque, exhaust gas recirculation (EGR) free design and Cummins-owned Holset® VGT™ turbocharger means the B6.7 is a leader in machine capability, simplicity, reliability and low total cost of ownership.