So, it turns out get_post_format and has_post_format for some reason are not working. I don’t know why it happened. I’m not familiar with the theme and wordpress code to track down the root cause but I have worked around the issue for now by bypassing those functions. So at least we got the featured images showing again.
Rolled back a few major versions to 1.09. And we see the same behavior. Other themes show the featured image. It may not be a specific version issue but something else related to the Gridzone theme. Any tip would be appreciated.
