Any thoughts?
It looks like you do more rolls per second. It can easily happen depending on how fast your internet is and how fast freebitco.in is.
If this is a problem for you, put a sleep (somewhere between 0.5 and 1s) between 2 rolls you make.
More rolls per second means, OP is trying to push the speed of freebitco.in than how usually it works?
Is it kind of automation rather than quickly clicking on the roll button manually? Even it sounds about own way of customizing, I guess it should be allowed by freebitco.in.
Because, I remember that @TheQuin once stated that making use of any bots is NOT allowed as per their TOS (I am sorry I could not locate such a post right away to link here).
OP,
Before working on any script for freebitco.in or any other gambling site, it would be a good practice to get permission from official people of those gambling houses to avoid later regrets.