Azure Logic App costs way more money than I'd expect; don't think I'm understanding the prices?

Question

I recently set up a Logic App in Azure to control automated tasks for a website, and its job is to send a single HTTP request to a task-management web service every 12 hours to initiate a few batched "cleanup" jobs. This app was on the consumption plan, which says it only charges you for the resources you use. However, I noticed that the Logic app was, by itself, accruing about $200/month in charges ($5/day). This is for sending only two HTTP requests every day, even though the pricing model says HTTP requests cost something like $0.003 per request (or something like that).

So I reached out to Microsoft tech support and got a prompt refund, and links to the pricing model, but it still makes literally no sense to me. They couldn't seem to explain why a Logic App that sent only (1) HTTP request to an endpoint every 12 hours would cost a relatively high amount of money.

The pricing model is listed here: https://docs.microsoft.com/en-us/azure/logic-apps/logic-apps-pricing, but it doesn't seem to have examples that are applicable to my situation. Can anyone explain why such a simple "pinger" app would cost so much?