Comment 5 for bug 2023585

I decided to disconnect the Nvidia GPU and use a spare AMD GPU and haven't had this occur since. I guess you're probably right that it's a hardware issue but don't know whether the fault was with the GPU or the Motherboard. At the time this was happening I had the Nvidia GPU in the first slot and the AMD GPU in the second PCIe slot but without any power cables running to it from the PSU, so essentially it was off and not being picked up by Ubuntu.

I don't know if the motherboard would be at fault or not in the scenario above if the second slot has a device plugged in but not powered? Initially it looks like the fault of the Nvidia GPU but I haven't tested it in other configurations to definitively say it's a fault with the Nvidia GPU.