What determines if Assets created by Load Assets get "NEXT" or an asset id?

Main Menu > Accounts Payable > Batch Processes > Extract and Loads > Load Assets Requests runs INTFAPAM which creates Assets which you can view in Main Menu > Asset Management > Send/Receive Information > Approve Financial Information > Review.

Sometimes the assets are generated with "NEXT" as their id, sometimes w/ an actual asset id. There doesn't seem to be a pattern - some ones in error get an asset id, some get NEXT, etc.

What determines whether the Assets created by INTFAPAM get an Asset ID or Not?