I updated my firefox from 119.0.1 to 121.0 two days ago, and have noticed a for my usage quite significant change:
When I have a page, say a search engine query or a gallery of links on a page, and I open one then go back, previously I got the cached version. Within reason of the cache size I could go back a few pages even days later and critically see them as they where, just like I would expect for a tab I have open.
I use this behavior to work through essentially todo lists, so now that the lists get reloaded every time I visit them, this combines with server side caching to make the list jump around quite annoyingly.
My expected behavior would be the cached back history being served when available, except when I manually hit F5.
Was this change intentional? Is there any way to get the old behavior back?
Edit:
It seems to be a bug and only happen on some profiles, potentially dependent on some metric related to heavy use, like number of open tabs and windows.
Edit:
It seems to be related to uBlock Origin.
Edit:
It is definitely an issue within ubo, I will add a link to the issue there when I create it.
Edit:
It seems to be caused by the "AdGuard Tracking Protection" filter list within ubo.
Edit: issues:
ubo filters: https://github.com/uBlockOrigin/uAssets/issues/21841
AdguardFilters: https://github.com/AdguardTeam/AdguardFilters/issues/170172
Edit:
It was fixed a few minutes ago, the changes should percolate through to ubo soon™. Thx Yuki2718.
I have Pinned it on uBlock Origin.
ubo seems to prevent creation of cache for pages while it is active.
Testing around with enabling and disabling addons, I saw the issue disappear. I then reenabled all addons and the issue was still gone. So I restarted and it came back. Then I disabled one after another, and got to it being ubo. I then tried disabling it, loading a "gallery page" and an entry on it, then reenabling ubo. The pages were still cached, but visiting a different entry would reload that one every time. Same for any other newly opened "gallery" and "entry" pages.
This explains why this didn't happen in the test profile, which has no addons installed, but the mirrored profile on the laptop does have ubo and ff on the same version, however I do not observe the behavior there. I will investigate further.
Actually it happens on the forked profile too now, restarting ff did not clear the cache there and it only occurs on newly opened pages now, so what I assume happened was I initially tested while ubo was not yet updated, since the laptop has been sleeping for a while. The browser generated a bunch of cache entries for my test pages and those continued working when ff updated ubo. Clearing the cache now has it break on all pages and fix itself when ubo is disabled like on the other device.
Therefore this seems like a clear ubo issue, independent of platform and other factors. All 3 affected profiles have similar ubo config, so I'll investigate that now. However it is not a firefox issue, I will move the issue elsewhere.