Using numpy random and pandas sample to make a random choice from a DF, not random distribution of choices after 100k runs

I have made a small script for my D&D group that, when a spell is cast, chooses whether or not another random spell gets cast, the ordinal spell gets cast, or nothing happens (with a 50%, 25%, 25% ratio, respectively).

In order to do this, I made a pd.DataFrame of every possible spell in the game (using data from http://dnd5e.wikidot.com/spells), and then appended two data frames (one that says "Original Cast" in the spell name and the other that says "Nothing Happens"), each with len == len(df)/2 so as to have a full df twice the size of the original, as shown in the code below.

import pandas as pdimport numpy as npfrom os import urandomdef create_df():    df = pd.read_csv("all_spells.csv", encoding="utf-8")    df = df.dropna(axis=0, subset="Spell Name")    df_b = df[~df["Spell Name"].str.contains(r"\((.*?)\)")].reset_index(drop=True)    OG_cast = ['Orginal Cast' for i in range(int(len(df.index)/2))]    No_Magic = ['Nothing Happens' for i in range(int(len(df.index)/2))]    Nadda = [None for i in range(int(len(df.index)/2))]    df_same = pd.DataFrame(columns=df.columns,                           data={                               df.columns[0]: OG_cast,                               df.columns[1]: Nadda,                               df.columns[2]: Nadda,                               df.columns[3]: Nadda,                               df.columns[4]: Nadda                           })    df_nothing = pd.DataFrame(columns=df.columns,                           data={                               df.columns[0]: No_Magic,                               df.columns[1]: Nadda,                               df.columns[2]: Nadda,                               df.columns[3]: Nadda,                               df.columns[4]: Nadda                           })    df_full = pd.concat([df_b, df_same, df_nothing], axis=0).reset_index(drop=True)    return df_full

df_full.sample(n=10) is shown below, for reference.

+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+|     | Spell Name                 | School        | Casting Time   | Range   | Duration                       | Components   |+=====+============================+===============+================+=========+================================+==============+|  12 | Psychic Scream             | Enchantment   | 1 Action       | 90 feet | Instantaneous                  | S            |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+|  18 | True Polymorph             | Transmutation | 1 Action       | 30 feet | Concentration up to 1 hour     | V S M        |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 670 | Orginal Cast               |               |                |         |                                | nan          |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 193 | Conjure Woodland Beings    | Conjuration   | 1 Action       | 60 feet | Concentration up to 1 hour     | V S M        |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 795 | Orginal Cast               |               |                |         |                                | nan          |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 218 | Otilukes Resilient Sphere | Evocation     | 1 Action       | 30 feet | Concentration up to 1 minute   | V S M        |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 353 | Levitate                   | Transmutation | 1 Action       | 60 feet | Concentration up to 10 minutes | V S M        |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 839 | Nothing Happens            |               |                |         |                                | nan          |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 459 | Silent Image               | Illusion      | 1 Action       | 60 feet | Concentration up to 10 minutes | V S M        |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+| 719 | Orginal Cast               |               |                |         |                                | nan          |+-----+----------------------------+---------------+----------------+---------+--------------------------------+--------------+

I then call the script below to get what happens when a spell is cast.

    df = create_df()    seed = int(np.random.uniform(0, len(df.index)*10))    spell = df.sample(1, random_state=seed)['Spell Name'].values[0]    print("The spell cast is:", spell)

To test if this was giving me the distribution I wanted (50% of the time, there is a random spell cast, 25% nothing happens, and 25% the spell works as intended), I ran

    OC = 0    NH = 0    N = 0    for i in range(100000):        seed = int(np.random.uniform(0, len(df.index)*10))        arb = df.sample(1, random_state=seed)['Spell Name'].values[0]        # print(arb)        if arb == 'Orginal Cast':            OC += 1        elif arb == 'Nothing Happens':            NH += 1        else: N += 1    print(OC, NH, N)

And instead of getting 50/25/25 (for the things stated above), I get an extremely consistent 47/26.5/26.5. Does anyone know why this is happening? And does anyone have a better idea and random sampling so as to more consistently get the correct ratio?