FBX Reference bones/animation are getting lost on import

We have 5 or so FBX animations that got updated to include a new bone that is on the character rig. These bones are camera helpers, they are not weighted to any mesh. Since the change only half of the animations got imported correctly. The rest seemed to drop the bones as the bone on the rig gets set to 0,0,0 when the animation plans. I've turned animation compression off to make sure it wasn't losing frames.

One strange thing was if I re-exported the exact same file I saved it as a different name and then again over the top of the existing one. The one with the new name actually started to work as expected while the old one did not. Thinking it was a cache issue I deleted my library folder and all my meta files for that animation and re-imported the anim files and it cleared to the file. However that did not fix the file, it seems like a roll of the dice of the bones get included or not.

The import rig is set to generic with a reference to our root node.

I'm not the artist who set the files up but it is possible that on some of these animations those particular bones do not have keys set but still they are parented to the root node.


I'm on Unity 4.0.0

 

I've track down the issue finally, animations were getting imported with first framing being 1 rather than 0. Unity was clipping the key that existing on frame 0 and thus things were broken. I would expect that if you were to trim the animation from the export settings that it would automatically replace the set the key for that new first frame using the data from keys prior to that point. This way you could trim out clips from an animation file. It seemed to work for the humanoid animations but not so on these generic animations.