GIGO ... Not really
, but that was the way those books came.
You just don't agree with those publishers.
Quality check Plugin to the rescue
Quality check Plugin: Check metadata: Check for Authors with commas (what you want fixed)
Select all results, <ctrl-a>
Quality check Plugin: FIX: Swap...
Note: only use on books with the issue.
Note2: CAN NOT fix when there are both ways in the Authors field
eg Smith, Mary & Sam Jones
Those will need your fingers typing
Look at all of what the QUALITY CHECK PI can help you with
