I'm in a game where the "End Buys" button failed to load, so I am forced to use all buys just to end the turn, even if I have to buy copper.
I see a lot of error messages in the JS console, like these:
Loading failed for images/materials/gold_button.jpg. raven-3.7.0.min.js:49:121
Loading failed for images/materials/stone_button.png. raven-3.7.0.min.js:49:121
Loading failed for images/materials/stone_button_small.png. raven-3.7.0.min.js:49:121
Loading failed for images/materials/copper_button_round.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/add.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/add-bot.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/bot.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/dice.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/exit.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/heart-small.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/heart-small-dark.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/heart-small-left.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/heart-small-right.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/indicator-off.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/indicator-on.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/lightning-small.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/lightning-small-dark.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/minus.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/play.png. raven-3.7.0.min.js:49:121
Loading failed for images/elements/debt_130.png. raven-3.7.0.min.js:49:121
If I expand one of them, I see this:
Loading failed for images/elements/close-button.png. raven-3.7.0.min.js:49:121
3]</e/t[n raven-3.7.0.min.js:49
t preloader.js:42
r raven-3.7.0.min.js:104
It may have been that around the time you posted the site was overloaded (from one other report). I would not expect the pictures to be affected on a browser or device that has played much Dominion before (they are cached), but if it was a new device or caches are not retained that might happen on overload.
I suspect that caching might not be working properly, because the base cards did not load from the cache.