Deferred Tax Requests

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We are using OnePica_AvaTax 2.4.3.2 in our Magento installation.
In some particular cases we create orders programmatically using cron scheduler.
We encountered the situation where tax request is sent to Avalara one hour after the order is created. It happens twice already and every time orders in question were created at 00:00 - 00:01 UTC. Tax requests for those orders were sent one hour later, at 01:00 UTC.
By that time orders with zero (wrong) taxes have been created already. Our Magento cron is starting every 15 minutes. Can you explain when and why such a deferred tax request is generated and what class in your module is responsible for handling situation like that?