BUG: Pandas group by aggregate sum returning nan for a big dataset with mostly float64 values and a very few null values

[ssdv1]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

Code:
neighborhood_stats = taxi_with_neighborhood.groupby('ntaname',dropna=True).agg({
    'cost_per_mile': ['sum','count']
}).reset_index()

Output:
ntaname	cost_per_mile
sum	count
0	Airport	NaN	470286
1	Allerton-Pelham Gardens	NaN	30
2	Arden Heights	NaN	3
3	Astoria	NaN	28449
4	Auburndale	NaN	40

Issue Description

`from azureml.opendatasets import NycTlcYellow
from datetime import datetime
from dateutil import parser
import geopandas as gpd
from shapely.geometry import Point
import pandas as pd

start_date = parser.parse('2015-01-01')
end_date = parser.parse('2015-01-31')

nyc_tlc = NycTlcYellow(start_date=start_date, end_date=end_date)
taxi_data = nyc_tlc.to_pandas_dataframe()

taxi_data.info()

neighborhoods = gpd.read_file('nyc/geo_export_efe01be6-5681-4d19-b441-eefd6f6bb3fa.shp')

geometry = [Point(xy) for xy in zip(taxi_data['startLon'], taxi_data['startLat'])]
taxi_gdf = gpd.GeoDataFrame(taxi_data, geometry=geometry, crs="EPSG:4326")

taxi_with_neighborhood = gpd.sjoin(taxi_gdf, neighborhoods, how="left", predicate="within")

taxi_with_neighborhood['cost_per_mile'] = taxi_with_neighborhood['totalAmount'] / taxi_with_neighborhood['tripDistance']

taxi_with_neighborhood.reset_index(drop=True, inplace=True)

neighborhood_stats = taxi_with_neighborhood.groupby('ntaname', dropna=True).agg({
'cost_per_mile': ['sum', 'count']
}).reset_index()

neighborhood_stats.head()

taxi_with_neighborhood['cost_per_mile'][0]

cost_per_mile_sum = taxi_with_neighborhood.groupby('ntaname')['cost_per_mile'].sum()

print(cost_per_mile_sum)

taxi_with_neighborhood_pdf = pd.DataFrame(taxi_with_neighborhood)

neighborhood_stats = taxi_with_neighborhood.groupby('ntaname', dropna=True).agg({
'cost_per_mile': ['sum', 'count']
}).reset_index()

neighborhood_stats.head()

pd.show_versions()
`

Expected Behavior

should return float values for sum

Installed Versions

INSTALLED VERSIONS

commit : 0f43794
python : 3.10.15.final.0
python-bits : 64
OS : Linux
OS-release : 5.10.0-32-cloud-amd64
Version : #1 SMP Debian 5.10.223-1 (2024-08-10)
machine : x86_64
processor :
byteorder : little
LC_ALL : None
LANG : C.UTF-8
LOCALE : en_US.UTF-8

pandas : 2.0.3
numpy : 1.24.4
pytz : 2024.2
dateutil : 2.9.0
setuptools : 74.1.2
pip : 24.2
Cython : 3.0.11
pytest : None
hypothesis : None
sphinx : None
blosc : None
feather : None
xlsxwriter : None
lxml.etree : None
html5lib : None
pymysql : None
psycopg2 : None
jinja2 : 3.1.4
IPython : 8.21.0
pandas_datareader: None
bs4 : 4.12.3
bottleneck : None
brotli : 1.1.0
fastparquet : None
fsspec : 2024.9.0
gcsfs : 2024.9.0post1
matplotlib : 3.7.3
numba : 0.58.1
numexpr : None
odfpy : None
openpyxl : None
pandas_gbq : None
pyarrow : 9.0.0
pyreadstat : None
pyxlsb : None
s3fs : None
scipy : 1.11.4
snappy : None
sqlalchemy : 2.0.35
tables : None
tabulate : 0.9.0
xarray : None
xlrd : None
zstandard : 0.23.0
tzdata : 2024.1
qtpy : None
pyqt5 : None