When a stock split happens, stock chart history and various statistics about the stock is updated to reflect the price change. This is the common practice everywhere. However, open and past positions for such a stock are not updated to reflect the price changes in T212. This results with misleading average price and return value after a split happens.
It is important to show originally paid amounts for each individual order in history, but I would at least expect to see adjusted values about the performance in my portfolio. This is usually handled in portfolio management apps when the split information is added, so this is also a common practice I think.
There will be stock splits for popular stocks in following days, and I already have such a stock in my portfolio which does not reflect the actual performance. It would be nice if this can be improved in future.