In the latest version on InDesign on cloud, the InDesign icon is missing when you save the file as document or template.
If you save as IDML, then the icon is purple. If save as Document the windows icon is blank white.
I also have this problem, seems the icon image is missing in the .dll file for indd files. idml files are ok.
Using indesign 16.0--2021
I also have this problem when I moved to 15.1.2 version. Or have to save as an in design mark up document - why?