Interesting - I'm also running self-hosted and didn't have this problem (I think my last image pull was about a month ago, though - so somewhat recent).

If you want, I believe you can override the update url in chrome to stop the auto-update process in the future: https://chromeenterprise.google/policies/?policy=ExtensionSe...

Alternatively, at least for chromium browsers - you can download the .crx directly, unzip it (p7zip will do it), and sideload it using the "Developer mode" checkbox on chrome://extensions. Firefox sadly doesn't support this - they'll remove any sideloaded extensions on browser close.