Hello @chefclarisseflon ,
From what I can see, this doesn't seem to be an actual error. It looks like you're running the flow twice with the same test user. In the first test, everything works correctly, but after that, it stops working because the user already has the tag assigned.
The first step is to confirm whether this is the real issue. To do that, go to your test user, manually remove the tag, and test the flow again. If it works correctly after removing the tag, then the issue is confirmed.
Once confirmed, consider whether this flow will be triggered more than once for the same user in real usage.
If the flow is sent only once per user, there is no problem.
However, if it might be sent more than once, I recommend adding an action to remove the "link_clicked" tag right after the user watches the video. This way, if the same user enters the flow again in the future, they won’t have the tag, and it will work as expected.