We’ve seen browsers behave differently in subtle ways. To mitigate impact while we figured out the correct fix, we’ve served different content to them so those

We’ve seen browsers behave differently in subtle ways. To mitigate impact while we figured out the correct fix, we’ve served different content to them so those users still get a working experience while we figure out and fix the underlying issue. This had nothing to do with feature detection, so the usual suggestions simply won’t work.