I find it kinda weird that Solomos reported it as normal defect and even prompted for fix update months later without making it clear it would make FF vulnerable to issue...

I doubt the "never" because it regularly shows me the wrong favicon. This has been true for so many years that I consider it a familiar quirk more than a bug...

> we have disclosed our research to all the browser vendors.

Please consider that the researchers apparently submitted TWO bug reports. One because functionally the cache is broken, one because there's a potential privacy issue.

    I also think that it would have been appropriate to notify about the
    ulterior motive behind this defect report at the latest when the paper got
    published. This underhanded approach of reporting a defect just leaves a bad
    taste, really.

    The behavior may be an actual defect in the classical sense, but I'm just
    wondering what would have happened, had this been addressed "in time" by the
    developers. It would seem that the researchers would then have triumphantly
    proclaimed that all major browsers are prone to their newly found attack.
    Must be somewhat disappointing that it didn't get fixed "in time" to make it
    into the paper that way.