Don't understand how/why CI/CD minutes are used up

Hey forum,

using Gitlab Free

today I received a notification that I should buy addition CI/CD minutes for my group. So I looked up why I got that notification and it turned out that
my CI/CD minute usage for November is 74% used, but I dont understand how and why.
I looked at the pipelines quota page and saw that only one project is apparently responsible for all the used minutes. It’s a game project I am currently working on.
296/400 minutes have been used since November. Now what I don’t understand is this:

I have another PC which serves as a buildmachine, TeamCity is installed on that machine and as of now I only have on configuration for that very project I am working on.
So far the project is setup for manual triggers, which means I trigger a build out from my IDE, and not by any pushes to the repository. And this month I havent triggered any manual builds.
How are the CI/CD minutes used when I am not even building anything? Or is a push to the repository, even when the buildmachine is not powered on, enough to count as usage?

Hi, check if Auto DevOps is not enabled, which would start pipelines on each push. It’s in Settings → CI/CD → Auto DevOps