Error frobbing /proc/sys/net/ipv6/route/skip_notify_on_dev_down: Expected current value to be 256, but found 0

Kernel: `Linux ubuntu 5.4.0-73-generic #82-Ubuntu` (focal)

```
Error frobbing /proc/sys/net/ipv6/route/skip_notify_on_dev_down: Expected current value to be 256, but found 0
```


```
root@ubuntu:~# cat /proc/sys/net/ipv6/route/skip_notify_on_dev_down
0
```