Most likely what’s happened is that there’s a batch program doing this job automated to run at a particular time, probably Friday night, which results in the e-mail Saturday morning. And whoever wrote this batch program forgot to include a line to exclude debts below a certain threshold. Even if somebody in Accounts Receivable notices and is annoyed by the sudden influx of checks for less than a dollar, unless that person has initiative and the knowledge of how to approach IT on the question, it could hang around through office inertia for a long time.

Given that publishers won’t pay creditors (i.e. authors) for amounts judged to be “too small,” in which “too small” = “considerably more than a dollar” until sometimes years after the debt is first incurred, when either enough money accumulates to cross the check-writing threshold or the book goes OP and they realize that’s all there’ll ever be, this is mighty stupid. But that’s life in the Big Corporation for you.