Before ppp-watch calls ifup-ppp, it checks what signals have arrived during sleep. The sigint is not in this list, though ppp-watch can receive it from parent ppp-watch attached to the terminal, if we press ctrl-c for example. Therefore ifup-ppp is called when it shouldn't (right before exit). A very simple patch fixes this.
Created attachment 18330 [details] patch to make ppp-watch not call ifup-ppp if it has received a sigint
Thanks, will be in 5.88-1.