eohm: thank you for your bug report and great job of your analysis of the root cause! Your PR works as expected, but I prefer to get the current core configuration rather than keeping our old copy longer than previously in main.c. I wrote a PR 9526 to reorganize the code to make it closer to the master branch: clarify the lifetime of the "local config" in main.c, and as soon as possible, switch to the core configuration attached to the interpreter state.