three.js canvas geometry panorama example renders incorrectly

[jdm]

https://threejs.org/examples/canvas_geometry_panorama.html
https://threejs.org/examples/canvas_geometry_panorama_fisheye.html

[nox]

#21004 and this one both uses THREEJS.PerspectiveCamera.

[nox]

The very first frame before the camera moves is already broken.

The black band of pixels on the right is not supposed to be there and the sky is supposed to be covering the entire window.

[nox]

For some reason, if I comment out renderer.setPixelRatio( window.devicePixelRatio ); it doesn't change anything in Firefox but the sky becomes twice as smaller in Servo.

[nox]

This actually has no WebGL involved and the demo was deleted from upstream 15 days ago when they removed CanvasRenderer.