diff --git a/pandas-stubs/core/indexes/accessors.pyi b/pandas-stubs/core/indexes/accessors.pyi
index 1ce5dfdb..735da79f 100644
--- a/pandas-stubs/core/indexes/accessors.pyi
+++ b/pandas-stubs/core/indexes/accessors.pyi
@@ -167,7 +167,7 @@ class _DatetimeRoundingMethods(Generic[_DTTimestampTimedeltaReturnType]):
     def round(
         self,
         freq: str | BaseOffset | None,
-        ambiguous: Literal["raise", "infer", "NaT"] | np_ndarray_bool = ...,
+        ambiguous: Literal["raise", "infer", "NaT"] | bool | np_ndarray_bool = ...,
         nonexistent: (
             Literal["shift_forward", "shift_backward", "NaT", "raise"]
             | timedelta
@@ -177,7 +177,7 @@ class _DatetimeRoundingMethods(Generic[_DTTimestampTimedeltaReturnType]):
     def floor(
         self,
         freq: str | BaseOffset | None,
-        ambiguous: Literal["raise", "infer", "NaT"] | np_ndarray_bool = ...,
+        ambiguous: Literal["raise", "infer", "NaT"] | bool | np_ndarray_bool = ...,
         nonexistent: (
             Literal["shift_forward", "shift_backward", "NaT", "raise"]
             | timedelta
@@ -187,7 +187,7 @@ class _DatetimeRoundingMethods(Generic[_DTTimestampTimedeltaReturnType]):
     def ceil(
         self,
         freq: str | BaseOffset | None,
-        ambiguous: Literal["raise", "infer", "NaT"] | np_ndarray_bool = ...,
+        ambiguous: Literal["raise", "infer", "NaT"] | bool | np_ndarray_bool = ...,
         nonexistent: (
             Literal["shift_forward", "shift_backward", "NaT", "raise"]
             | timedelta
diff --git a/pyproject.toml b/pyproject.toml
index 9b967bf5..c22fd5b6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ mypy = "1.15.0"
 pandas = "2.2.3"
 pyarrow = ">=10.0.1"
 pytest = ">=7.1.2"
-pyright = ">=1.1.396"
+pyright = ">=1.1.396,!=1.1.398"
 poethepoet = ">=0.16.5"
 loguru = ">=0.6.0"
 typing-extensions = ">=4.4.0"
diff --git a/tests/test_io.py b/tests/test_io.py
index cca219c4..0397629e 100644
--- a/tests/test_io.py
+++ b/tests/test_io.py
@@ -43,7 +43,6 @@
 from pandas._testing import ensure_clean
 import pytest
 import sqlalchemy
-import sqlalchemy.ext.declarative
 import sqlalchemy.orm
 import sqlalchemy.orm.decl_api
 from typing_extensions import assert_type
diff --git a/tests/test_timefuncs.py b/tests/test_timefuncs.py
index e8d2e477..40ee3295 100644
--- a/tests/test_timefuncs.py
+++ b/tests/test_timefuncs.py
@@ -489,16 +489,31 @@ def test_series_dt_accessors() -> None:
         pd.Series,
         pd.Timestamp,
     )
+    check(
+        assert_type(s0.dt.round("D", ambiguous=False), "TimestampSeries"),
+        pd.Series,
+        pd.Timestamp,
+    )
     check(
         assert_type(s0.dt.floor("D", nonexistent=dt.timedelta(1)), "TimestampSeries"),
         pd.Series,
         pd.Timestamp,
     )
+    check(
+        assert_type(s0.dt.floor("D", ambiguous=False), "TimestampSeries"),
+        pd.Series,
+        pd.Timestamp,
+    )
     check(
         assert_type(s0.dt.ceil("D", nonexistent=dt.timedelta(1)), "TimestampSeries"),
         pd.Series,
         pd.Timestamp,
     )
+    check(
+        assert_type(s0.dt.ceil("D", ambiguous=False), "TimestampSeries"),
+        pd.Series,
+        pd.Timestamp,
+    )
     check(assert_type(s0.dt.month_name(), "pd.Series[str]"), pd.Series, str)
     check(assert_type(s0.dt.day_name(), "pd.Series[str]"), pd.Series, str)
     check(assert_type(s0.dt.unit, TimeUnit), str)