diff --git a/run_test.sh b/run_test.sh
index 01c4930..b0b0886 100755
--- a/run_test.sh
+++ b/run_test.sh
@@ -169,7 +169,8 @@ for PY_VER in $PY_VER_UNIT_TESTS; do
             # Write output to file. Make variant w/ omitted line numbers for easy diffing / CR
             PY_VER_MYPY_TARGET=$(echo "$1" | cut -d. -f1-2)
             export MYPYPATH=$MYPYPATH:test/generated
-            mypy --custom-typeshed-dir="$CUSTOM_TYPESHED_DIR" --python-executable="venv_$1/bin/python" --python-version="$PY_VER_MYPY_TARGET" "${@: 2}" > "$MYPY_OUTPUT/mypy_output" || true
+            # Use --no-incremental to avoid caching issues: https://github.com/python/mypy/issues/16363
+            mypy --custom-typeshed-dir="$CUSTOM_TYPESHED_DIR" --python-executable="venv_$1/bin/python" --no-incremental --python-version="$PY_VER_MYPY_TARGET" "${@: 2}" > "$MYPY_OUTPUT/mypy_output" || true
             cut -d: -f1,3- "$MYPY_OUTPUT/mypy_output" > "$MYPY_OUTPUT/mypy_output.omit_linenos"
         }
 
diff --git a/test_negative/output.expected.3.8 b/test_negative/output.expected.3.8
index 0153adf..c9d4c1b 100644
--- a/test_negative/output.expected.3.8
+++ b/test_negative/output.expected.3.8
@@ -74,7 +74,7 @@ test_negative/negative.py:179: error: "_r_None" has no attribute "invalid"; mayb
 test_negative/negative.py:183: error: Incompatible types in assignment (expression has type "ValueType", variable has type "str")  [assignment]
 test_negative/negative.py:185: error: All overload variants of "DummyServiceStub" require at least one argument  [call-overload]
 test_negative/negative.py:185: note: Possible overload variants:
-test_negative/negative.py:185: note:     def [_MTVDummyService0 in (UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService1 in (UnaryStreamMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply]), _MTVDummyService2 in (StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService3 in (StreamStreamMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply])] DummyServiceStub(self, channel: Channel) -> DummyServiceStub[UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply]]
+test_negative/negative.py:185: note:     def [_MTVDummyService0 in (UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService1 in (UnaryStreamMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply]), _MTVDummyService2 in (StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService3 in (StreamStreamMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply])] __init__(self, channel: Channel) -> DummyServiceStub[UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply]]
 test_negative/negative.py:192: error: "DummyReply" has no attribute "not_exists"  [attr-defined]
 test_negative/negative.py:193: error: "DummyReply" has no attribute "__iter__" (not iterable)  [attr-defined]
 test_negative/negative.py:198: error: "DummyReply" has no attribute "not_exists"  [attr-defined]
diff --git a/test_negative/output.expected.3.8.omit_linenos b/test_negative/output.expected.3.8.omit_linenos
index 5e7a04a..d8ea051 100644
--- a/test_negative/output.expected.3.8.omit_linenos
+++ b/test_negative/output.expected.3.8.omit_linenos
@@ -74,7 +74,7 @@ test_negative/negative.py: error: "_r_None" has no attribute "invalid"; maybe "v
 test_negative/negative.py: error: Incompatible types in assignment (expression has type "ValueType", variable has type "str")  [assignment]
 test_negative/negative.py: error: All overload variants of "DummyServiceStub" require at least one argument  [call-overload]
 test_negative/negative.py: note: Possible overload variants:
-test_negative/negative.py: note:     def [_MTVDummyService0 in (UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService1 in (UnaryStreamMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply]), _MTVDummyService2 in (StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService3 in (StreamStreamMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply])] DummyServiceStub(self, channel: Channel) -> DummyServiceStub[UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply]]
+test_negative/negative.py: note:     def [_MTVDummyService0 in (UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService1 in (UnaryStreamMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply]), _MTVDummyService2 in (StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply]), _MTVDummyService3 in (StreamStreamMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply])] __init__(self, channel: Channel) -> DummyServiceStub[UnaryUnaryMultiCallable[DummyRequest, DummyReply], UnaryStreamMultiCallable[DummyRequest, DummyReply], StreamUnaryMultiCallable[DummyRequest, DummyReply], StreamStreamMultiCallable[DummyRequest, DummyReply]]
 test_negative/negative.py: error: "DummyReply" has no attribute "not_exists"  [attr-defined]
 test_negative/negative.py: error: "DummyReply" has no attribute "__iter__" (not iterable)  [attr-defined]
 test_negative/negative.py: error: "DummyReply" has no attribute "not_exists"  [attr-defined]