Stop loss activated at the wrong time

[baptisteberard]

Hello, i'm new to trading.

 

On my demo account, i bought some credit agricole stocks 7.6 each and put a stop at 7.5255.

 At 15:54 the stocks were automatically sold, as you can see in the picture, 

But at the time, the price was at 7.6696.

th

I tried again and had the same problem at 16:51

Is there something i'm missing about stops? Does this happens with a real account?

Thanks for your answers and have a nice day!