The following workaround seems to have worked for me -
I noticed that my icon image files were created in different color spaces. The light and the dark files were in RGB whereas the tint version was Gray. And for some reason, App Store Connect was pulling the tint version.
So I recreated the tint version. I changed the colors of the elements to grayscale (in the authoring tool), but saved the file in RGB color space.
Then re-submitted the binary with the updated icon files to App Store Connect and it seems to have worked. App Store is now extracting the light version from all these apps.
Hope that helps.
Topic:
App Store Distribution & Marketing
SubTopic:
App Store Connect
Tags: