I am not familiar with ProtoVPN; there is not a way to do this with OpenVPN of which I know. (I used that too in the past.)
Maybe I misunderstood, but I thought you asked if any client did this in general. IPVanish (Windows) does, and I used it when I was their customer, so I chimed in. They implemented that function within their particular client. As I mentioned, at least functionally, everything was suspended when this happened. I did not see an IP address exposure, but I could have missed it. (I was not on the network continuously, so I eventually got annoyed when this happened, and I turned it off.)
My current service does not implement the function. When I was searching for a new service with proper Linux support, the field narrowed and I did not see this feature anywhere else.