Bug Report: execution time increased by ~33% with 3.12 image

**Describe the bug**

We upgraded to 3.12 yesterday and found that the execution time increased from ~30m to ~40m. I re-ran on 3.11 in a different branch earlier and found it took ~33m, in line with earlier measurements.

For comparison, I ran the tests locally and got ~27m on 3.11, and ~25m on 3.12.

**To Reproduce**

Not sure, as this is a private project.

**Expected behavior**

I would expect to see similar if not better results on 3.12.

**Screenshots**

This is how master looks like for the past 7 days:


**Additional context**

I'm curious whether this is something that others have experienced, and what are some steps we could take to debug this etc.