"Il libro è breve."
The pronunciation of the word "breve" is incorrect, there shouldn't be stress on the first "e" .
It sounds to me like too much stress on the second "e," but perhaps that is what you meant. Either way, I agree there is something not quite right about it, and, for once, the problem report doesn't include a category for the sound. They say "do not report mistakes here," but what is one to do when there is no other option? I think under "report a problem," there should always be an "other" category, with a chance to give feedback they may not anticipate, but in any case, something related to the recorded/spoken language should always be included.