Based on the current information, I am guessing that there may be a YAML file in your "Staging" branch with the same name as the YAML file used to create the pipeline.

If such a file exists in "Staging" branch, please check whether there is a trigger section in the YAML.

1. If "Disable implied YAML CI trigger" is not enabled and no trigger section is added in the YAML, then the YAML pipeline is configured by default with a CI trigger on all branches.

   You can set trigger to none to disable the CI trigger OR enable "Disable implied YAML CI trigger" settings in your project settings.

   See details from CI triggers.

2. If there is trigger session and "Staging" branch is a trigger branch, please remove it.

If there isn't such YAML file in "Staging" branch, please share a screenshot of the build summary page of the CI triggered build. URL format is https://dev.azure.com/{orgName}/{projectName}/_build/results?buildId={buildId}&view=results.