Tesla Stock Split

There is going to be a Tesla stock split, where the record date is the 17th of August. As I understand it, the distribution date is 26th August.

I bought 5 Tesla shares in my NABTRADE account a few months ago. When I logged on today, my account is showing 15 Tesla shares worth USD $13,679, and along with a HUGE profit - which can’t be right.

Has NABTRADE made some sort of mistake whereby if I see the ’15’ shares today, I’d make a huge profit, or is that not physically possible?? If I try and sell the shares, what will happen? When I load up the sell page, it shows that I can sell 15 shares, and it is showing the Tesla price to be the current price of USD $911. If I sell, will the trade go through?

I'm really confused about this.