Upgraded to 185.18.36 (from ports) today. Rebooted the system but nvidia.ko wasn't loaded
(thus, errors like "Failed to initialize the NVIDIA kernel module..." in Xorg log).
Here's where it gets strange. The module does not show up in kldstat output, but kldload
KLD nvidia.ko: depends on kernel - not available
kldload: can't loadnvidia.ko: File exists
...and `kldunload nvidia.ko` also fails with "kldunload: can't find file nvidia"
I downgraded to 185.18.29, and the problem remained!
My kernel has not changed, nor have I made any significant configuration changes recently.
 I should mention that there's no unusual output in dmesg except the error above when attempting to load the module manually. nothing about nvidia.ko appears during the boot sequence