Again you're full of assumptions.

We're very proactive in our compat outreach and we've had numerous conversations with sites like Google. Sites like Google are VERY aware of the CV list & the modes they're rendering in; it's not a surprise to them.

Don't assume we're doing something nefarious when it's not the case. We have nothing to gain (and a lot to lose) by breaking one of the top web properties, even if they're a competitor.

Here's a more plausible scenario. Google may have made a change to their SERPs which didn't work great in the docmode that IE11 is rendering it in. Nothing intentional, nothing nefarious on either company's part.

I think that's a more reasonable explanation than the concerns you're expressing.