Can't anymore drag and drop or paste files from Finder to my app iCloud Ubiquitous container

I can't drag and drop or paste files anymore from Finder to my app iCloud Ubiquitous container.

My app used to be an iOS (iPad) only app that I recently ported to the Mac using Catalyst. This problem may have started after moving to Monterey or more likely after I ported my iOS app to the Mac. Before that, I had not problem dragging pdf files to my iCloud Ubiquitous container from Finder. In fact this was one of the main way my iOS app could get new content so I know it used to work (other way is to save a file from another app that can export pdfs)

Now I get the no drop cursor icon. I can duplicate files, create folders, drag out files, deleted files, save new files from other apps... just can't drag and drop or paste files into the iCloud Ubiquitous container folder from Finder. Also can't "Get Info" on the iCloud Ubiquitous container.

The only workaround I found is to use iCloud Drive app from iCloud.com. Drag and Drop works just fine there?????

Any idea what broke in my container?

Thanks

H-