Apple Mail not displaying 'Click to Download' link for Mail Dropped files

I sent myself a handful of pictures via Mail Drop (total size ~48MB) on my Mac. Message sent successfully.

The resulting email in my Inbox does not display a 'Click to download' link. I can see the 'Download full resolution images' and expiration date in the Side Preview pane for the email, but the actual email message does not display the link - only the small thumbnails of each image. The only way I was able to access the full sized photos stored in iCloud was to enable the 'View All Headers' option and copy the link under 'Image-Archive-Url:'

For reference, I am sending (and receiving) on a gmail account set up in Mail. When I log into gmail from Safari, I see the download link. When I access the email from my iPhone, I see the download link.

I am running Catalina 10.15.1, but I see the same issue on a Mac mini running El Capitan 10.11.6..

Any insight would be appreciated!