registeredTemplates is used as a filter on the subscription to the transaction stream used by the trigger. So if you do not include T2, the trigger will never see transactions containing T2 and therefore those contracts will not be shown in the ACS.
There is currently no way to limit firing the rule to specific events while still updating the ACS. There are two situations if we get an event for T2:
- Either your ACS is in a state where your trigger rule will emit commands, then firing it is the right thing to do and that will modify the state in some way, e.g., by adding contracts to the pending set.
- Or your ACS is not in a state where your trigger rule will emit commands. The worst thing that can happen here is that you waste some computational resources. For a lot of triggers figuring out if you have to do anything is fairly cheap so this is often not an issue. If you do something computationally expensive here you could consider using the custom user state that stores enough information to make that check cheap again instead of having to recompute that information from the ACS everytime the trigger rule fires.