I can turn on minify in the general settings section of the wp admin, but if I visit the subpage and try to change settings, e.g. HTML enable, inline etc, then I get a 403 error. I am using WP in a subdirectory, which after reading some posts could be an issue. But why do settings update on every other subpage and not Minify?
I've submitted a bug report, I'm also getting the blank screen issue with Page Caching turned on.