Cash deposit & a trade. results differ if done using PC based windows or Mac. Browsers don't matter!

[Raed]

Hey guys.

I am using Macbook Pro with Chrome:

I started a portfolio under my account:

Step: 1 Deposit of Cash Date: Nov 7, 2013, Amount 1,949.53. Clicked add to portfolio

result was the empty portfolio with balance of $1,949.53 in green (which is fine)

Step: 2 type a symbol TWTR clicked on add transaction data, Confirmed its BUY, date Nov 7, 2013, shares 41, price 46.94, Commission 24.99, confirmed deduct from cash is clicked. then clicked add to portfolio.

result: wrong data showing when I choose Overview or Performance tab. instead showing balance is 0.00 it shows balance is -$509.88 and its in red.

I couldn't figure out the reason why as I did it over and over again. however I then decided to do it on another computer it and happened to be a PC windows based internet explorer. I followed the exact steps above with a new portfolio and this time the result was correct. balance 0.00

I went back to my Mac tried it again on Chrome. Same wrong result. I tried Safari & Firefox both on Mac and both results were wrong: same -$509.88

below screenshot shows results when portfolio is created on a Mac: Chrome, Safari or Firefox. all have the wrong results and same error by -509.88

Below shows the correct results. but This portfolio was created using a Windows Based PC computer. I then when back to my mac to check the portfolio. view using Mac was fine so the screenshots were made on a Mac 

I notice many of you have cash balance drops on this FORUM. this could be the reason. are you using Mac? its a really weird Bug. But no matter what I do. Results are perfect on windows based computer. On a Mac all browsers seem to get it wrong by the exact same figure.

Any ideas?