If I export a STEP of a board with a round internal edge (Edge.Cuts) using the circle tool, the inner hole is not generated. The issue should be very easy to recreate. It looks ok in the 3D-viewer:
Yes, this is a bug.
It’s already reported on gitlab, but the issue opener set it “confidential”, so it’s not visible to all gitlab users. The “priority” was raised to “high”, so I guess it will be fixed in v8.0.1.
What is the procedure for reporting such issue, should I report it somewhere else?
Yes, if you are sure you have discovered a error then open a issue on the gitlab bugtracker. You will need a gitlab account for that.
My recommendation is to use the Kicad built-in function “Help–>Report Bug”. This creates a new gitlab issue, and prepopulates the “Kicad version” section with the needed information.
The remaining part is to fill the “Description” and “Reproduction steps” section. It’s also good if you can attach a example project (in your case for instance with a working rectangular and a non working round hole).
See also the FAQ-article: I found a bug. What now?