So, from your question, I’m unsure whether you have found the option to actually add an action after end of palletizing, or you’re adding actions after the palletizing sequence.
There’s an option in the Pallet command, which enables either actions to be added before palletizing or after palletizing. Enabling this will open up a new branch of the Pallet command, where you can add actions that are executed when all items have been palletized.
If you are actually referring to this yourself, and it is causing you issues, then there’s probably something wrong with the setup of your Pallet, because it has always worked AFAIK.