It seems to drop notes occasionally. The place where it drops them in a track is reliable, but it only happens the first time on load, after that a subsequent play works fine. X3 doesn't seem to have the same issue.
 
Is this just me?

Sycraft . . . are you waiting for all the samples to load ?
My BFD3 takes a while to load all the samples, so I can't hit play right away, or there will be dropped notes.
I've done quite a bit of export / rendering with BFD3 in Sonar Platinum, and it works the same as X3e, so far.
Don't know what your system is like, but I try to keep all my sample drives defragmented for optimum performance as well.

Ya all the samples are loaded fully. I wait to make sure, but this actually doesn't happen until a bit in the track.  Actually X3 has no problem even if I don't wait. Only the new platinum has an issue. Bfd lives on a dedicated ssd just for it so samples load fast. I have a pretty heavy hitting system (5930k, 32gb ram, 3 ssds) so it handles things pretty gracefully. 
 
The reason I'm curious and getting more information is that it only occurs in platinum. Same track in X3 has no issues. Also it isn't like it has lots of issues, but they seem reproducible which indicates a possible bug. 
 
So just seeing if others have a similar experience.