Error not in AD Workbench but yes in the submission enviroment

ADDI Alzheimers Detection Challenge
#1

This error appears only during submission and not in the AD Workspace.

cat_encoder = load_object('cat_encoder')

X_cat = pd.DataFrame(cat_encoder.transform(test[['intersection_pos_rel_centre']]).toarray())

X_test = test.drop(['row_id','intersection_pos_rel_centre'],axis=1)
X_test = X_test.join(X_cat)
X_test.head()
-----------------

ValueError: Input contains NaN

The error appears here:
X_cat = pd.DataFrame(cat_encoder.transform(test[['intersection_pos_rel_centre']]).toarray())

The thing is that there are NaNs but I have checked and it is already a category, and this is not a problem in the AD Workspace but only in submission enviroment.