iCloud Drive Error Opening File

For some files I have in iCloud Drive I can't open them from Finder on my mac mini.

They show error ‘The file <filename> couldn’t be opened’ when I try to open them.   

Trying to copy these files in Finder returns 'Finder cant complete the operation because some data cant be in “file name” can’t be read or written (Error code -36)'.

cp command in Terminal returns Input/output error.

Disk Utility shows no errors.

Files aren’t locked.  Permissions are Read/Write for my user.

I logged into iCloud in Safari to see if the file opens from there...and it's not there…, so somehow it only exists now on my mac mini.

It's a handful of files, in different folders.  I don’t see  a pattern why it's happening to these files only.

Any ideas?