Pinpoint opts out email endpoints, even if opt out is explicitly disabled

I'm adding email endpoints with the SDK for JavaScript v3 call below.

    await pinpoint.send(new UpdateEndpointCommand({
        ApplicationId: PINPOINT_APP_ID,
        EndpointId: email,
        EndpointRequest: {
            Address: email,
            ChannelType: 'EMAIL',
            OptOut: 'NONE',
            User: {
                UserAttributes: {
                    CognitoId: [cognitoId],
                    FirstName: [firstName ?? ''],
                    LastName: [lastName ?? '']
                }
            }
        }
    }))

I'm not running another endpoint update for this email later. I do run a PutEvent command later, tested with and without the OptOut: NONE field.

However in the segment, when I do an export, the endpoint is marked as OptOut: ALL. Why is that?

I previously didn't set the OptOut value but had the same result. The docs say it's optional, but don't specify a default. Might be good to add info on that.