Can't give you an answer on the legal or not, but it is according to where the information came from. Most sites have disclaimers as to the content because the site administrator has no control over who is entering the data and whether or not it is correct.
Legal? I'm not sure it's illegal, if that's what you mean. Most agents are meticulous in listing details about their property listings, but there are a few that don't pay too much attention. That's why there is a disclaimer on the bottom of most MLS listing Sheets & Online listings usually stating something to the effect "information is deemed accurate, but not guaranteed".
What happened? If you give us more details, we can better answer your question.