Bosch active line noise under load (crunchy, whirring)

[striated]

Note the noise in the first few seconds of the clip. It's under load on my urban arrow front-hauler going uphill on an enviolo hub. It flattens out later in the clip and the noise goes away.
It's making a crunchy whirring noises that seems to resonate throughout the motor consistently under heavy load. The noise seems to only be there when e-assist is on. Not present when I'm only pedaling.
Thoughts?
It's from a bike from 2016 but the motor was replaced at some point(by orig owner).