After three days, I ended up just editing the FEX page and selecting "Change Repository" and setting it to the same repository again, at which point the FEX page immediately refreshed with the new version.
What's strange is the Version History section now indicates that it picked up the new version 2 days ago, despite the fact that it never actually showed up in either browser until I forced a change to page. Maybe it did and somehow both my browsers were stuck on a cached version of the page? I doubt that, but either way, bumping the repo link fixed it.
