This is a known thing that happens with bad drivers, they can mess with user-mode FP flags. For a while (IIRC) Cisco's VPN software was corrupting FP state and

This is a known thing that happens with bad drivers, they can mess with user-mode FP flags. For a while (IIRC) Cisco's VPN software was corrupting FP state and causing Firefox to hang/crash, for example. At a previous company we had to run a dll in our web servers (provided by the payment processing company) for PCI compliance reasons, and we later discovered it was messing with our FP flags and as a result serialization code was producing invalid floats. That was a fun one.