I think my assumptions were correct.
PP Core was missing. I certainly hadn’t deleted it.
Was working just fine Sep 3rd. Notice that PP Core plugin updated on Sep 4th.
So, decided best option was to re-upload PP Core plugin. Done. Activated.
Permissions settings now re-appeared (naturally). Checking functionality now – appears to be back working as before.
However, very concerned PP Core was deleted / removed apparently following plugin update. Not good for a production site, if my assumptions are correct.
I occasionally see this when updating a plugin (though I’ve never seen it with PP Core). It happens infrequently enough that I’ve never pursued an explanation or solution. In my opinion, the best policy is to update plugins manually and pay attention to the displayed captions. As you discovered, if a file / folder update error prevents installation of the new files after the old files are already deleted, you simply re-install the plugin.
None of my code is involved in the file update operation from ww.wp.xz.cn.
Thanks for the update Kevin, much appreciated.
FYI – I update all plugins via WPRemote. Many WP installs to manage; simply not effective to update each one separately / manually.
Personally, I don’t think I’ve never experienced a plugin (or file) being deleted without my knowledge. Certainly, I’ve not known WPRemote to cause this issue previously. Maybe I’ve been lucky.
It just seemed too much of a coincidence that it was working fine Sep 3, the plugin was updated Sep 4, and sometime between Sep 3 and Sep 6 it stopped working on my site (i.e. Core plugin was deleted).
Anyway, all’s good, for now. Again, thanks for your reply.