Plugin installed, only disk caching enabled. However, page cache never has any pages in it (checked folder on disk). Logs show that plugin is fetching pages, but pages never appear in cache. No errors shown on page, no errors in logs. Tuned on page cache debugging, but no debug info appearing in pages. It's almost like the plugin isn't hooking into wordpress correctly.
I am seriously considering trying another plugin, the only reason I have not switched is that is is a regression; it worked before and then randomly stopped working, probably after an update. Also, I checked the permissions and what not, it's all fine. I also reinstalled the plugin and deleted the settings; same issue.
Only possible problem I can see is that the blog is in a subdirectory instead of on the root. There could be a bug related to detecting that properly.