Ad_Bugs table and merged patches question

Recently upgraded an instance from 11i to R12.1.3. As part of post-upgrade patches we applied merge patch that included several other patches. For some reason, Ad_Bugs table was not updated for this merge patch. All other patches before and after this merge patch seems to show up in ad_bugs. The merge patch was applied successfully. We have verified some of the new functionality that we were expecting to see. The merge patch show up in ad_applied_patches table but nothing in ad_bugs table.
Need to understand why this information is not in ad_bugs and need to verify that all patches were applied correctly through the merge patch.