diff --git a/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_false.py b/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_false.py
index be5e0cc15a..b214371dc2 100644
--- a/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_false.py
+++ b/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_false.py
@@ -51,7 +51,7 @@ def time_since_previous_false(datetime_col, bool_col):
             df.loc[not_false_indices, "last_false_datetime"] = np.nan
             df["last_false_datetime"] = df["last_false_datetime"].fillna(method="ffill")
             total_seconds = (
-                df["datetime"] - df["last_false_datetime"]
+                pd.to_datetime(df["datetime"]).subtract(df["last_false_datetime"])
             ).dt.total_seconds()
             return pd.Series(total_seconds)
 
diff --git a/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_true.py b/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_true.py
index b237a5357b..cf86d2eeef 100644
--- a/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_true.py
+++ b/featuretools/primitives/standard/transform/cumulative/cumulative_time_since_last_true.py
@@ -46,7 +46,7 @@ def time_since_previous_true(datetime_col, bool_col):
             df.loc[~not_false_indices, "last_true_datetime"] = np.nan
             df["last_true_datetime"] = df["last_true_datetime"].fillna(method="ffill")
             total_seconds = (
-                df["datetime"] - df["last_true_datetime"]
+                pd.to_datetime(df["datetime"]).subtract(df["last_true_datetime"])
             ).dt.total_seconds()
             return pd.Series(total_seconds)