Help. Responsive image style does not obey sizes attribute.

I have a responsive image style set up like this:

Breakpoint group:
Responsive image

1X Viewport sizing []:
Select multiple image styles and use the sizes attribute

(min-device-pixel-ratio: 1.25) 1664px, (min-resolution: 192dpi) 1664px, 832px

Image styles selected:
Small (832×416)
Large (1664×832)

Properly sized images are stored in the correct locations, but the style always returns the large image. I even changed Sizes to:
(min-device-pixel-ratio: 1.25) 832px, (min-resolution: 192dpi) 832px, 832px
and I still get 1664px images. The only way I’ve been able to get the 832 images is by deselecting the Large image style.

Arrgggh. What am I doing wrong?


Drupal version: