Thanks for uploading that pp2 file so we could take a closer look!
It is indeed some very strange behavior. Without knowing more about how your network is configured it's hard to say for sure but it looks like there may be an issue with your router setup. 10.0.0.1 and 10.1.10.1 are both internal private IP addresses and that's where the weirdness is happening. You are getting the gray lines because PingPlotter isn't expecting anything to be there. When it switches over to the 126.96.36.199 IP then you get a brief instant of graph tracing and then it switches back.
The 188.8.131.52 IP address belongs to Grand Rapids Comcast Cable Communications Llc so that's your ISP. It may be something with how your cable modem is configured. You could do a factory reset on it and see if it solves the issue. If that doesn't help, if you lease the modem, I would encourage you to ask for a replacement unit.
If you have any other questions let us know, we're happy to help!