When you have an active running torch on an interface ( pppoe interface for example ) , when that interface gone (for example pppoe disconnects) causes 100% cpu in the router until you hit the stop button in torch.
on which version of ROS?
I have tested in >= 3.10 but i think it is in 3.x and if i correctly remember it was in 2.9.x also
stop torch, re-enable interface and everything should be back to normal. After that you can run torch again without any problems. Tested on 3.16