Automation: checklist created trigger runs more than once

[Jan Legutko]

Hi,

I have a scheduled job that every month creates a card with a checklist 'X'. I have automation rule that adds 8 items to checklist 'X' whenever it's created. 

I created all this in July. So the first time the card was created, it added the checklist with 8 items - all good. But for August it was 16, in September 24 and in October 32... And for November 40. 

I added a test card and added the checklist manually but it worked fine. 

What's wrong? What should I change so that I will have only 8 intended points added to my checklist in the newly created card?