Some few minutes ago, a question was migrated from MathOverflow.
I left a comment on the original question that suggested that the question wasn't suitable for MathOverflow, and while it is suitable for MSE, it is not the case for its current form, and so it should be edited and have details added before it is re-posted.
Unfortunately, at least three users on MathOverflow chose to migrate instead of closure, despite the fact that the question wasn't edited yet.
But when the migrated thread appeared, my comment was missing. On the other hand, a comment made by another user was preserved through the processes.