diff --git a/pytential/qbx/__init__.py b/pytential/qbx/__init__.py
index e05a80635060b634348e6302e77502c43ca784a2..d5d52ca6daa575484ae621ded4668179c01f1266 100644
--- a/pytential/qbx/__init__.py
+++ b/pytential/qbx/__init__.py
@@ -491,8 +491,13 @@ class QBXLayerPotentialSource(LayerPotentialSourceBase):
 
     def exec_compute_potential_insn(self, queue, insn, bound_expr, evaluate):
         from pytools.obj_array import with_object_array_or_scalar
-        from functools import partial
-        oversample = partial(self.resampler, queue)
+
+        def oversample_nonscalars(vec):
+            from numbers import Number
+            if isinstance(vec, Number):
+                return vec
+            else:
+                return self.resampler(queue, vec)
 
         if not self._refined_for_global_qbx:
             from warnings import warn
@@ -502,7 +507,7 @@ class QBXLayerPotentialSource(LayerPotentialSourceBase):
 
         def evaluate_wrapper(expr):
             value = evaluate(expr)
-            return with_object_array_or_scalar(oversample, value)
+            return with_object_array_or_scalar(oversample_nonscalars, value)
 
         if self.fmm_level_to_order is False:
             func = self.exec_compute_potential_insn_direct
diff --git a/pytential/symbolic/execution.py b/pytential/symbolic/execution.py
index 213eb42827840ea4c4af770778953ee58bacfb99..96cac5c4f5074bfb74f8a7460855894210095c26 100644
--- a/pytential/symbolic/execution.py
+++ b/pytential/symbolic/execution.py
@@ -266,7 +266,7 @@ class BoundExpression:
         :arg domains: a list of discretization identifiers or
             *None* values indicating the domains on which each component of the
             solution vector lives.  *None* values indicate that the component
-            is a scalar.  If *None*,
+            is a scalar.  If *domains* is *None*,
             :class:`pytential.symbolic.primitives.DEFAULT_TARGET`, is required
             to be a key in :attr:`places`.
         """