Earlier versions of AutoPatch (adpatch) would automatically check whether the
prerequisites for the current patch were installed properly.  An important change to the AutoPatch defaults was made in the Applications DBA Minipack 11i.AD.I.2 release:  automatic checks for prerequisite patches are now disabled by default. 

When you run AutoPatch AD.I.2 and higher, sharp-eyed DBAs may notice the following warning: 
  Attention: AutoPatch no longer checks for unapplied pre-requisite 
  patches. You must use OAM Patch Wizard for this feature. 
  Alternatively, you can review the README for pre-requisite 
  information.
As of AD.I.2 and higher, if you want prerequisites to be checked, you now must explicitly pass the parameter options=prereq to AutoPatch in addition to any other parameters that you may already be passing.  For example: 
  $ adpatch options=prereq

This was a somewhat controversial decision within Development.  Proponents for disabling prerequisite checks correctly note that certain patches won’t apply even when their prerequisites have been applied as part of other combined patchsets. 

The downside of this new default behavior is that you may end up applying a patch without knowing that the prerequisites are missing.  This is a particularly tricky problem to debug when dealing with technology stack patches.

So, our standing recommendations are to check a patch’s README carefully, or just add the options=prereq parameter manually when running AutoPatch.