Sadly, there are far too many websites that don't handle splits properly. There is no 'CAN' there is only 'MUST'.
If a bullish company stock price rises to $100 per share and the company decided to do a 6 for 1 stock split. Can moving average be computed taking the stock split into account? If it doesn't than wouldn't the bullish signal turn into a bearish signal do to the 6 for 1 stock split? Also if the moving average interval is short (like 10 days) it will be sensitive to this price change, giving a false signal.