Yeah, I think that must've been the problem all along, the api cache clearing setting was erasing everything, since they were all using the same folder. You might need to patch the program to write those different caches to different subfolders automatically, yes?
Question: Since the api cache is set to expire every six hours anyway, what does it need a clearing setting for? Should I just set that to 0? I think 20 was the default, so I just left it there.
Also: Whenever someone goes to a page, if there's no cache for it already, their visit triggers a cache write, correct? Then the next person gets the cached info, and so on until the cache expires, right? So, if we're getting enough visitors, maybe I don't even need the caching script. If that's the case, I may experiment with removing the cron job, now that we've solved the disappearing cache problem.
Yeah, 750 seems to be fine, since it's able to write to it. However, all the cache directories I created (html-cache, api-cache, html-template) changed to 750 by themselves - I think your plugin must be doing it, don't you? Don't know what else would cause it, it doesn't happen to any other directories.
One other issue: The main video shown (the big one at the top) for each page in pagination is the same as the first pagination page. Shouldn't it change to show the first video on each page?