diff --git a/domain/modelling/optimisation/optimiser.py b/domain/modelling/optimisation/optimiser.py
index 4a5edd28e..73f5e9a1a 100644
--- a/domain/modelling/optimisation/optimiser.py
+++ b/domain/modelling/optimisation/optimiser.py
@@ -260,10 +260,9 @@ def optimise_package_fabric_first(
     # with the phase-1 overlays, so candidates are valued against the
     # fabric-applied dwelling and the resulting package score stays the
     # truthful whole-package figure against the original baseline.
+    consumed: set[int] = _used_group_indices(groups, fabric_package.selected)
     remaining_groups: list[list[ScoredOption]] = [
-        group
-        for index, group in enumerate(groups)
-        if index not in _used_group_indices(groups, fabric_package.selected)
+        group for index, group in enumerate(groups) if index not in consumed
     ]
     post_fabric_scorer = _PrefixedScorer(
         scorer, [scored.option.overlay for scored in fabric_package.selected]