Silly Green Monkey
Cowardly Lurking in the Shadows of Greatness
How do you know this?. In the case of the LBT, there so far has been nothing else added to the differential that meets all the observations.
One does not just toss out the only thing on the dif list because something you aren't aware of might be the actual diagnosis. You test the hypothesis and if it fails you continue looking.
You don't seem to allow for even the remotest possibility that anything else might be on the dif list. Some have been suggested, grind types, times ground, different cuts from the cow, cooking types, length of time under the warmer--that's only a small sample of the innumerable factors that can affect ground beef from source to ingestion. LBT might even be the cause of the problem you noticed----but at this time you don't have the evidence to conclude that.