We shipped a backend update to our forum today. The change makes it so that notebook ‘previews’ on long threads are only loaded if you click the “load preview” button. We made this change to improve load times of long threads. Threads with 3 or fewer notebooks are unchanged, but those with 4+ notebook attachments will now only load the notebook preview in the original thread, and any other notebooks will have to be clicked in order to load. Note that you will need to click to load before you can clone a notebook.
Thanks to Vedran Rusman for pointing out that this was a growing problem in recent challenge threads!
P.S. If you ever want to automatically load all the previews in a long thread without clicking them one by one, you can append
?show_all=1 at the end of the thread’s URL.