“Unfortunately, some important measurements serving as markers for liver function were not conducted for technical or unknown reasons.”
The authors don’t know why certain tests were not conducted? That’s unusual to say the least.
It sounds to me rather like the Monsanto scientists were trying to give their bosses a fig leaf. "Yeah, we found that it causes organ damage, but, uh, we should probably do some more careful tests, because you really can't tell anything from those organ damaged rats."