i’m new at wordpress and i’m having a similar problem too.
after i edit a post, i click on update and it still reverts back to the old post! i’ve tried five times and it still does that. i’ve tried deleting caches or cookies. i don’t want to switch to the default theme, i’ve already worked hard on editing some of postings that they might change if i revert back to the default theme.
and why do i need deactivate plug-ins? i only need want to update a post, why is it so hard to do that??