For the "Vendor data valid, but not enough received." folks that are also Intel iGPUs, try this in the GPU Stats configuration UI...
Set (or confirm) that "UI Automatic Refresh / Interval (Milliseconds):" is not lower than 1000.
Set "Intel_top_command_timeout:" to "1 .9"
My system is getting older (Coffee Lake / Gen8) and I've noticed that the stats panel is having trouble when my system is really bogged down.
Hope this helps someone!