I don't know what's happening, but all of the sudden users are complaining that they can't see recent comments by others (or any at all). They say that if they POST a comment, then they can see all the missing comments.
One user sent me the HTML for one of my blog pages, and the WP Super Cache comment at the bottom of the page said the page had been generated 5 days ago.
There are lots of comments made on all my posts, including this one. I have always expected WP Super Cache to regenerate a post when it receives comments. I'm all over these pages, logged in, and they should be regenerated many times a day.
I just had a thought...
Some time, not so long ago, I installed a new version of WP Super Cache and I think it changed some settings. In any case, I went through the settings and set them to recommended values or what I thought made sense. One of the CHANGES I think I made was to set the Caching parameter to mod_rewrite instead of whatever it was (probably PHP). Could that lead to confusion as to what pages get served? Would clearing the cache help that (which I just did)? I remember that WP Super Cache told me that my Mod Rewrite code needed updating, which I let it do.