We have found some issues with patch management when upgrading to BCM 12.6.
September 22, 2017 Update: The fix ( BCM 12.6.0 Patch 1 (BuildNumber 170915o) is now available on the BMC electronic product download site. Support Central - BMC Software
Here are the items we have found, including one workaround.
DRZKZ-1572 - After upgrading to 12.6 Patch Management Database update fails on Patch Manager with Bulk Products Error
* Workaround: The workaround is to run a sql script each time the master starts. This can be done using the Sqlrun section of the Vision64database.
DRZKZ-1564 - SQL Errors on Patch Job evaluation after 12.6 upgrade and first Patch KB update
DRZKZ-1563 - SQL error on PatchLanguages table during 12.6 upgrade
DRZKZ-1560 - After upgrade 12.5 -> 12.6, it is not possible to change the patch manager
DRZKZ-1589 - Some patches downloaded previously to the upgrade are not installable
DRZKZ-1590 - Service pack Ids are not matching anymore after upgrade to 12.6