I'm running WordPress 3.2.1 in Network mode.
I have Pretty Link Pro enabled.
When Object Cache is enabled in W3TC, I can't save options in some plugins. Most notably to me is Pretty Link Pro. It won't write to the database at all.
But as soon as I disable Object Cache, I can change the options in my plugin (in this case, Pretty Link Pro) and the changes are saved.
Interestingly, removing "plugins" from the "non-persistent groups" list fixed this problem on one of my sites, but not another.
Here's a video demonstration of what's happening:
I don't think this initially happened when I upgraded to 0.9.2.4. It started when I tried optimizing my site after receiving a notice of CPU cycle overage from my web host.
Please help me figure this out!