I had very similar problem with two cameras. I think it is the driver bug. The way we tried to go around it was to use default camera names and "attach" them to the cameras (that is, cam0 was always doing triggered acquisition, cam1 is in free run etc). Note that if you would remove one out of four cameras, the settings will become invalid as the cameras will be renamed.
NI 1394 driver is not the best thing on Earth, to be honest. I think, they would rather sell you something like 1422 or at least 1409, not the driver.
Michael