Do you mean the graphics weren't loading? Was the spoiler text still visible? There is an issue where sometimes it gets confused and "thinks" it loaded and so it stops showing the spoiler text (there as a placeholder until the card graphic finishes loading). There are some things in the options menu to help with that, like clearing out the card data from your memory cache (so it knows to re-reload them) or just downloading the whole thing so that it is there in your memory.
Note: really bad with using proper computer jargon so if something I said sounds stupid, I probably just butchered the wording. ^^' I will say I recommend using the official Pokémon TCG Online forums as they usually have stickied posts about these kinds of things.