I'm running into this error when only using Autoloader within my UC.   So, my assumption is that when Autoloader does  a file listing for my source files, it creates the error.   I've tried pointing Autloloader to an s3 location (a public bucket) and also a /Volume path that is mapped into my unity catalog.  Both generate the same error.

I have no problems with a similar attempt outside of UC using my hive_metastore which I share with my AWS instance.

My metastore path is unspecified but my catalog path is specified.