Compare http://musicbrainz.org/doc/Sandbox with http://wiki.musicbrainz.org/Sandbox.

I remember that classic, test, and locally installed dev servers did not have this issue - they did not cache anything and always showed the latest version of docs that weren't in the table. However, sometime yesterday/today test also started caching (classic still doesn't).

Interestingly, if I add a page to the table (at which point it shows a specific version, old or new) and then remove it, the page falls back onto the perma-cached version instead of the latest version.

It looks like the only way to update documentation for now is to add the page to the table.