CentOS - Mar 2017 - Nvidia related kernel panic on boot, *unless* the keyboard is tapped

So here is an odd one

Ever since the upgrade to 7.3, when using the el-repo kmod-nvidia, boot 
hangs around the 'mounted /boot' point. If left it then kernel panics

However at that point, tapping the keyboard gets it going again. As I'm 
using a wireless keyboard, even the act of switching the keyboard on 
gets it going again

This doesn't happen without the kmod, and I'm in the process of 
capturing the panic to file the bug report with el-repo, but for the 
sake of conversation has anyone seen anything like this before, or have 
any idea why that could happen?

cheers

Dunc