Memory usage change doesn't make sense for new review app

When creating a merge request, on the first push to the branch, a review apps is created, and a deployment is mentioned on the MR widget. With k8s and Prometheus, there's also a notice about a change in memory. But this is a new app, with only a single deploy. How can there be a change? I don't even know where that first value is coming from since nothing on the monitoring graph has that low memory usage. (In this case, it says Memory usage increased from 1.47MB to 7.52MB)

/cc @joshlambert