I wouldn't say that a PCIe to Firewire is a non-standard configuration. This is a perfectly normal thing to have if you need a firewire port - many high-end audio devices over the years have been Firewire. I still use an RME Fireface 800 which requires a card in my PC. Most of the companies building DAW PCs offer this as an option.
Having said that,
@Dannexus if MOTU hasn't updated drivers and you didn't install new drivers from Fractal then I would take a look at the release notes for any updates to Windows over the last couple weeks to see if they updated anything in the driver stack or perhaps pushed out new drivers for PCIe, Firewire, etc.