I noticed this (and took the screenshots) last night, there was a period about 11.30 to at least 00:10 GMT last night, in which the price displayed by the MTGox feed was different from the price quoted on the website by up to +-$3/btc
I noticed the feed went down yesterday at about mid-afternoon so I wonder is this a technical fault. In any case it is really worrying.
Also, there were some huge price swings while this was happening. Are bots trading off the feed data? Could that explain this crazy swing:
Has anyone else noticed this? Can we get some comment from MtGox on this issue?