Hi Andy,
The 12A shown in the DRV8873 is greater than the OCP threshold, and causes the device to disable the outputs.
Instead enabling the brake at 100%, please try lowering the duty cycle for a short time (10ms?) and then brake at 100%.
The goal is to minimize the current spike when braking at 100% to less than 10A. Ideally if you can lower the current further, this should minimize the chance of an overtemperature event disabling the outputs.
The 12A shown in the DRV8873 is greater than the OCP threshold, and causes the device to disable the outputs.
Instead enabling the brake at 100%, please try lowering the duty cycle for a short time (10ms?) and then brake at 100%.
The goal is to minimize the current spike when braking at 100% to less than 10A. Ideally if you can lower the current further, this should minimize the chance of an overtemperature event disabling the outputs.