Mine has always uploaded automatically until the last week. With Assassin's Creed 4 it auto uploaded once, and after that never did again.

First yes I do realize that this was posted about 2 years ago, but I can tell you what the problem is if anyone still needs to know, and comes across this.

It's specific versions of the router that does this. Mine is a version 8.0, and it done exactly what was said. However, it's actually a problem with the routers firmware. Go to linksys's website and download the newest firmware for your router. It actually even states that it fixes a UPnP problem with the router. After the firmware is installed via the router settings page 192.168.1.1 your problem router reseting problem shouldn't exist any more.