The server determines the item(s) you get from a case as soon as you open it. The actual case "animation" is a separate thing that only happens on your client based on the item that the server has added to your inventory. Due to some funky math stuff the animation can be off in rare occasions. This has no effects on your actual odds or the items you will receive. Due to the clientside nature of this issue you will most likely not be refunded.

The server determines the item(s) you get from a case as soon as you open it. The actual case "animation" is a separate thing that only happens on your client based on the item that the server has added to your inventory. Due to some funky math stuff the animation can be off in rare occasions. This has no effects on your actual odds or the items you will receive. Due to the clientside nature of this issue you will most likely not be refunded.