I see it quite frequently as well. It started last Feb. I emailed Audiogon and they said it was due to a programming error. They also lost quite a bit of selling/buying data that we used to be able to pull up. That is why the format is different as well. Some parts were not compatible with the new operating system and programming language.
Why is it that when I look up the seller info...
for some sellers I get a start date of 1969 (may have seen other "wrong" dates as well)?