I do not know if that's the case whatever the cache, but on my end I use Boost and if I just hit Save, the META tag won't appear on the front page until I go there and manually delete the cache. There is an easy function call to make to clear the cache and I think it would be handy to have that directly in this module.
What do you think?
It does not seem logical to have it in Boost, otherwise that would mean Boost should support all modules... It would be a nightmare.