Description
Pandas version checks
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I have checked that this issue has not already been reported.
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I have confirmed this bug exists on the latest version of pandas.
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I have confirmed this bug exists on the main branch of pandas.
Reproducible Example
import pandas as pd
import numpy as np
df = pd.DataFrame()
df['idx1'] = [0,1,2,3,4]
df['idx2'] = [0,1,2,3,4]
df['abool'] = True
df['a'] = np.arange(5, dtype='int64')
df['b'] = np.arange(5, dtype='float64')
df['c'] = np.arange(5, dtype='int64')
df = df.set_index(['idx1','idx2'])
idx = [(1,1),(3,3)]
df.loc[idx, 'c'] = 0
df.loc[idx, 'c']
df.loc[idx, ['a', 'b']] # This line is the problem
df.loc[idx, 'c'] = 15
df.loc[idx, 'c']Issue Description
In Pandas 1.4.x the last line is not showing the change in the column c and the values still being 0.
>>> idx1 idx2
1 1 0
3 3 0
Name: c, dtype: int64
When I call the column c as DataFrame I get the correct values
df.loc[idx, ['c']]
>>> c
idx1 idx2
1 1 15
3 3 15
Expected Behavior
On Pandas 1.3.5 I get
>>> idx1 idx2
1 1 15
3 3 15
Name: c, dtype: int64
Installed Versions
INSTALLED VERSIONS
commit : 66e3805
python : 3.8.12.final.0
python-bits : 64
OS : Windows
OS-release : 7
Version : 6.1.7601
machine : AMD64
processor : Intel64 Family 6 Model 60 Stepping 3, GenuineIntel
byteorder : little
LC_ALL : None
LANG : None
LOCALE : Spanish_Chile.1252
pandas : 1.3.5
numpy : 1.23.1
pytz : 2022.1
dateutil : 2.8.2
pip : 22.2
setuptools : 59.8.0
Cython : None
pytest : None
hypothesis : None
...
xarray : None
xlrd : 2.0.1
xlwt : None
numba : None