When aser manages scope via scope_stacks but a sub-expression falls through to the CEK machine, context/emit!/emitted couldn't find the scope frames (they're in scope_stacks, not on the kont). Now the CEK special forms fall back to env-bound primitives when kont lookup fails. 2568/2568 tests pass (was 2566/2568). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>