It's at extreme angles. The last gen Pixel does it too, but it's more yellow than blue. The S8 and Note 8 do it also, but there's is more red. Long story short, a whole lot of AMOLED displays do this.
Its not only at extreme angles it is at the slightest angle lets be honest here. I've seen 2 display models and 1 retail and I can tell you it made no difference. I love the phone but we cannot ignore the fact that the screen has issues.