a) Does this 'heal' if you double-click the folder to view the contents? If you restart Finder? *
I have notified that there are sometimes problems with the caching that finder does so that newly deposited files do not appear even though a terminal session shows that they are there. Noticed this since early Mac OS X almost 20 years ago, although has been less noticeable for me lately. In the past, I would sometimes need to exit the Downloads folder, or restart Finder, to see a newly downloaded file in that folder. Not sure if has been fixed, but I do not recall the last time I observed this (reported) behavior in Finder.
b) If the folder is not readable then you would not see the '>' but the icon should also have a minus.
* On Big Sur, you and restart Finder process by holding down the option key and clicking Finder icon in the Dock.