Vendors Eliminating Themselves from Competitive Sales Situations

We have recently seen vendors eliminate themselves unnecessarily from very competitive sales situations (sometimes even when there were only two finalists left), based on their own estimations of where they stood in the bake-off.  In the most recent of these, two vendors were tied for top pick as the proof-of-concept approached.  One vendor somehow concluded that the other vendor had already won, and got extraordinarily negative in tone.  The client then eliminated the negative one.  But in reality, it was the vendor that eliminated itself.  The client was mystified.