diff --git a/python/cudf/cudf/core/column/string.py b/python/cudf/cudf/core/column/string.py
index 8e90b0c4fc6..5a37af68eed 100644
--- a/python/cudf/cudf/core/column/string.py
+++ b/python/cudf/cudf/core/column/string.py
@@ -5948,7 +5948,7 @@ def __contains__(self, item: ScalarLike) -> bool:
 
     def as_numerical_column(self, dtype: Dtype) -> NumericalColumn:
         out_dtype = cudf.api.types.dtype(dtype)
-        if out_dtype == "b":
+        if out_dtype.kind == "b":
             with acquire_spill_lock():
                 plc_column = plc.strings.attributes.count_characters(
                     self.to_pylibcudf(mode="read")
@@ -6024,11 +6024,10 @@ def strptime(
             add_back_nat = False
 
         with acquire_spill_lock():
-            plc_dtype = dtype_to_pylibcudf_type(self.dtype)
+            plc_dtype = dtype_to_pylibcudf_type(dtype)
             result_col = type(self).from_pylibcudf(
                 casting_func(self.to_pylibcudf(mode="read"), plc_dtype, format)
             )
-        result_col = casting_func(self, dtype, format)
 
         if add_back_nat:
             result_col[is_nat] = None
diff --git a/python/cudf/cudf/core/tools/numeric.py b/python/cudf/cudf/core/tools/numeric.py
index ab414b2eebd..caf0e537e09 100644
--- a/python/cudf/cudf/core/tools/numeric.py
+++ b/python/cudf/cudf/core/tools/numeric.py
@@ -231,9 +231,9 @@ def _convert_str_col(col, errors, _downcast=None):
             return col.astype(dtype=cudf.dtype("float64"))
     else:
         if errors == "coerce":
-            col = col.astype(np.dtype(np.float64))
             non_numerics = is_float.unary_operator("not")
             col[non_numerics] = None
+            col = col.astype(np.dtype(np.float64))
             return col
         else:
             raise ValueError("Unable to convert some strings to numerics.")