This is not a bug and it has always worked this way. We use a 24 hour moving average of the exchange rate to adjust vendor's prices, not the up-to-the-minute exchange rate you see in the bottom left. So, when the price moves quickly, there can be a discrepancy between these two rates. That's the point though, we don't want sharp intraday fluctuations in the exchange rate to push the prices on the site all around.