Confusing on Closed Merge Request Events

### Jenkins and plugins versions report

Environment

```text
Paste the output here
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### What Operating System are you using (both controller, and any agents involved in the problem)?

Windows 10
Chrome

### Reproduction steps

First, I didn't checked Closed Merge Request Events in Jenkins Plugin,
But, when I closed a merge request, it did trigger the closed events

### Expected Results

Only I checked Closed Merge Request Events, it triggers after I closed a merge request

### Actual Results

I didn't checked Closed Merge Request Events, it triggers after I closed a merge request

### Anything else?

I don't know why it triggers?