diff --git a/src/atomate2/vasp/sets/base.py b/src/atomate2/vasp/sets/base.py
index 5dd52353d0..82429658bc 100644
--- a/src/atomate2/vasp/sets/base.py
+++ b/src/atomate2/vasp/sets/base.py
@@ -312,6 +312,8 @@ class VaspInputGenerator(InputGenerator):
     force_gamma: bool = True
     symprec: float = SETTINGS.SYMPREC
     vdw: str = None
+    # copy _BASE_VASP_SET to ensure each class instance has its own copy
+    # otherwise in-place changes can affect other instances
     config_dict: dict = field(default_factory=lambda: _BASE_VASP_SET)
     inherit_incar: bool = None
 
diff --git a/tests/vasp/test_sets.py b/tests/vasp/test_sets.py
index f07e2b5a8c..c9cecb0c63 100644
--- a/tests/vasp/test_sets.py
+++ b/tests/vasp/test_sets.py
@@ -2,6 +2,7 @@
 from pymatgen.core import Lattice, Species, Structure
 
 from atomate2.vasp.sets.core import StaticSetGenerator
+from atomate2.vasp.sets.mp import MPMetaGGARelaxSetGenerator
 
 
 @pytest.fixture(scope="module")
@@ -172,10 +173,10 @@ def test_set_u_params(structure, request) -> None:
         (10, {"KSPACING": 0.44, "ISMEAR": -5, "SIGMA": 0.05}),
     ],
 )
-def test_set_kspacing_and_auto_ismear(struct_no_magmoms, bandgap, expected_params):
-    static_set = StaticSetGenerator(auto_ismear=True, auto_kspacing=True)
-    # need to indicate to atomate2 to use KSPACING instead of KPOINTS
-    static_set.config_dict["INCAR"]["KSPACING"] = 42  # dummy value
+def test_set_kspacing_and_auto_ismear(
+    struct_no_magmoms, bandgap, expected_params, monkeypatch
+):
+    static_set = MPMetaGGARelaxSetGenerator(auto_ismear=True, auto_kspacing=True)
 
     incar = static_set._get_incar(
         structure=struct_no_magmoms,