This is just a simple bug. The ASE parser has a list of the non-deterministic functions that it should disallow when creating a user defined function. When the new deterministic functions getutcdate(), current_date(), and current_time() were added to ASE, they were not added to the list of functions not allowed in UDFs. Change Request (CR) 727121 is open on this, but is considered very low priority.
-bret