Yes, lately, with 11.2, at least, NVidia has been iffy for me. One machine, I had to manually add the PCI Bus ID, then, when that disk went bad, I decided to do a reinstall on another disk, and it didn't work, while Fedora Linux worked out of the box.
I used the port, but I _think_ that the package now works, now that 11.1 is EOL, but didn't try it. (With the package, you also need Linux, with the port, not necessarily, haven't retried with Linux support yet and won't get to it till Sunday).
I suspect you mean RELEASE, rather than STABLE. In FreeBSD, STABLE is sort of in between RELEASE and CURRENT. Fred Cash wrote a very good explanation during the time of 4, 5, and 6, I think, that's still accurate, that can be seen here. NVidia's package was NOT working on 11.2, you had to use the port, and it wasn't documented anywhere. Did you use the package or the port? If the package, try with the port. It DOES work, at least most of the time (the box I'm using has always been a bit iffy, and as I said, I did have to add the PCI Bus ID, which I didn't have to do on any other machines.