It seems like "kdesrc-build --initial-setup" doesn't have this problem, just the TUI setup wizard.
Git commit 50894549d28fd9fa1fdef17c815e5b3c1a4274e7 by Nate Graham. Committed on 26/05/2021 at 18:20. Pushed by ngraham into branch 'master'. Don't set deprecated option in setup "ignore-kde-structure" has been removed in favor of "directory-structure", which has a default value of "invent" M +2 -3 kdesrc-build-setup https://invent.kde.org/sdk/kdesrc-build/commit/50894549d28fd9fa1fdef17c815e5b3c1a4274e7