[toomuchcoffee]

"we can't find your final interviewer"

This is clearly disingenuous, and accomplishes nothing other than to to convey a palpable sense of contempt and disregard for the candidate. It's an insult to their intelligence, basically.

[typpo]

This is not an unusual practice. For example, Microsoft has been known for sending people home early for quite some time. In some cases they'll tell you the next guy is out of work today (which is disingenuous), in other cases they'll tell you that you're done and send you home.

Not giving candidates a set schedule of interviews beforehand prevents these awkward lies and interactions. This may be an acceptable level of honesty because rejecting someone on the spot can be very difficult, both for the interviewer and the candidate.