title: scikitlearn ValueError: precomputed is True but the input data is not a mask
body: <p>I have a pipeline:</p>
  <pre><code>feature_cleaner =  Pipeline(steps=[
      (&quot;id_col_remover&quot;, columnDropperTransformer(id_cols)),
      (&quot;missing_nearZero_remover&quot;, missingRemover())
  ])
  
  zero_Setter = Pipeline(steps=[
      (&quot;zero_imp&quot;, ZeroImputer(fill_zero_cols))
  ])
  categorical_transformer = Pipeline(steps=[
      (&quot;categorical&quot;, SimpleImputer(strategy='constant', fill_value='unknown')),
      ('encode', OneHotEncoder())
  ])
  
  numeric_transformer = Pipeline(steps=[
      ('imputer', SimpleImputer(strategy = &quot;constant&quot;, fill_value=-1, add_indicator=True)),
      ('scaler', StandardScaler())
  ])
  preprocess_ppl = ColumnTransformer(
      transformers=[
          ('numeric', numeric_transformer, make_column_selector(dtype_include=np.number)),
          ('encode', categorical_transformer, make_column_selector(dtype_include=object))
      ], remainder='passthrough'
  )
  
  pipeline = Pipeline(
      steps=[
          ('zero_imputer', zero_Setter),
          ('cleaner', feature_cleaner),
          (&quot;preprocessor&quot;, preprocess_ppl),
          #(&quot;estimator&quot;, customOLS(sm.OLS))
          ]
  )
  </code></pre>
  <p>before running this pipeline, I do convert the datatype of the dataframe:</p>
  <pre><code>data = data.convert_dtypes()
  </code></pre>
  <p>I am getting this error:
  <a href="https://i.stack.imgur.com/5C0kI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5C0kI.png" alt="enter image description here" /></a></p>
  <p>Anyone has idea what this is about?</p>
  <p>Also, I dont use the <strong>convert_dtypes()</strong> then I get this error:</p>
  <pre><code>Encoders require their input to be uniformly strings or numbers. Got ['float', 'str']
  </code></pre>