VT has many advanced level words that are mispronounced.
VT website quotes:
The VT website says "Just use the link at the bottom of the play page to let us know of a problem with a particular word, and we'll do our best to make improvements." And this was a 2008 press release:
"We're extremely proud to announce that the Visual Thesaurus now offers accurate, high-quality audio pronunciations for every single word in our database Ã¢â‚¬â€� all 150,000 of them!"
VT still has 3-year-old corrections to do. Correction: Now the mispronunciations are 5 years old.