We ran a breakage study near the end of last year. First-Party Isolation (FPI) did have the highest breakage scores: ~18-19% of users reported problems with it

We ran a breakage study near the end of last year. First-Party Isolation (FPI) did have the highest breakage scores: ~18-19% of users reported problems with it, and 9-10% of FPI users disabled the study. Those are low relative numbers, but at entire-market scale, they are big absolute numbers. :/ https://blog.mozilla.org/data/2018/01/26/improving-privacy-without-breaking-the-web/ https://blog.mozilla.org/data/2018/01/26/improving-privacy-w...