Answer

Not a bug
Looks like you have exceeded the maximum of 250 stocks per portfolio OR 400 stocks across all your portfolios

Oh, that makes sense. Thank you. Something you may want to have the app developers do is add a message like "You have exceeded the max number of stocks" message as there is no check and balance saying that the stock didn't add to the portfolio. Thanks again.
Customer support service by UserEcho
Thank you for your feedback. We are looking into it.