When executing jobs on an AIX Agent, the first JOBS ran every 10-15 minutes will fail with a return code 126 but all subsequent JOBS will be successful until this cycle repeats.
This has only been seen with:
Release : 12.3
Component : AUTOMATION ENGINE
This was identified to be caused by a failure in an installed active directory agent not properly merging local and active directory user and group permissions.
This was resolved by updating the OS components to the latest versions after confirming a known defect on the OS level.