Have you tried simplifying the location of the file and the name so that it does not exceeds 27 letters?
There used to be a bug when either linking Xref or Mods that if the total amount of "letters" either in the file name or in a particular folder were it resides exceeded the old Mac OS maximum of 27 letters it would not be able to link to it.
I know that it is a long shot but it might be worth a try.
Also, have you tried to hotlink the file to another AC file to see if the error is the file or in TW?
Eduardo Rolón AIA NCARB
AC28 US/INT -> AC08Macbook Pro M1 Max 64GB ram, OS X 10.XX latest
another Moderator