Hi, @Mike ,
As you are using a 3rd party tool to migrate, which is out of the scope of this forum, it is hard to say whether the tool modified anything in your source library which may trigger the alert. Per my knowledge, the alert shall send email about details of the modification, what have you seen in the Email? And if there is no alerts sending in next week, we may consider it could be a single event due to the migration.
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