The way to interpret PingPlotter is by starting at the final destination, 8.8.8.8 in your case, and work your way back through the route to see if you can identify where that same pattern of packet loss was first introduced.

Since the packet loss you're seeing at hop 1 doesn't really match that at 8.8.8.8 then we can assume they're unrelated. Your router is probably just ignoring the echo requests PingPlotter is sending it when it gets a little busy. This is pretty common especially when the TTL value of those requests is 0. You can read more about this here.