The delays in seeing the result of the roll are caused by lag on the internet. If it keeps on rolling and doesn't stop that just means your end didn't get the response from the server. All rolls are instant on the server and the spinning is just an animation. Either the roll request gets to the server and is processed or it doesn't. Any internet lag cannot affect the result.
I suggest you do some research on provably fair and learn how to verify your own rolls. That really is the point of provably fair - you can prove it to yourself. That means you don't have to take anybody's word for it.