Copy Item to another list triggers workflow on that item

What actions are you performing in the action before copying it? There is something in the workflow that is editing the current item and thus triggering the workflow to run again.

The copy item action wouldn't trigger that since its creating a new item, so there is something else there causing this to happen.

Thank you for the quick answer.

Yes, the workflow changes some fields, but that was not an issue before I added the copy item part.

The workflow worked perfectly until I put this in, now it is always trigerred twice

edit: I just found the answer by myself: I saved the original list as template and used that template to generate the archive list. Somehow this seems to be an issue. I built the archive new from scratch and now it works as intended.

Interesting. Yes because you were using a copy of the list, the workflows could have been triggering on the archive list based on some hidden metadata on the list that was captured in the workflow bindings. Not exactly sure, but I've seen that happen on-prem before with the workflow engine. 

A fresh list does help in this case. Glad you got it resolved.