It is the icons that are missing. That is, they are not specific to the file.
Update:
[1] Most of the missing icons represent Windows Explorer shortcuts, i.e. ".lnk" files. If I select an item with a bad icon and then use the dialog to fix the icon, the item seems to be repaired. (There is one however that I cannot fix in this manner.)
[2] With the exception of the one unrepairable item mentioned in [1], the other files whose icons were wrong were Windows symbolic links, i.e. "symlink"s. If I replace the symlinks with Explorer shortcuts, the icons return. It would seem that Start11 cannot handle Windows symlinks.
Conclusion:
Start11 [a] should have a way to repair its icon cache and [b] it should be able to handle symbolic links.