BUG: `pd.concat` dataframes with different datetime64 types

[Charlie-XIAO]

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

>>> import pandas as pd
>>> df1 = pd.DataFrame({"a": range(2), "b": range(2)}, dtype="datetime64[s]")
>>> df2 = pd.DataFrame({"a": range(2), "b": range(2)}, dtype="datetime64[ns]")
>>> pd.concat([df1, df2])
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "D:\Academic\Open Source\pandas-yxiao\pandas\core\reshape\concat.py", line 390, in concat
    return op.get_result()
  File "D:\Academic\Open Source\pandas-yxiao\pandas\core\reshape\concat.py", line 678, in get_result
    new_data = concatenate_managers(
  File "D:\Academic\Open Source\pandas-yxiao\pandas\core\internals\concat.py", line 198, in concatenate_managers
    return BlockManager(tuple(blocks), axes)
  File "D:\Academic\Open Source\pandas-yxiao\pandas\core\internals\managers.py", line 988, in __init__
    self._verify_integrity()
  File "D:\Academic\Open Source\pandas-yxiao\pandas\core\internals\managers.py", line 995, in _verify_integrity
    raise_construction_error(tot_items, block.shape[1:], self.axes)
  File "D:\Academic\Open Source\pandas-yxiao\pandas\core\internals\managers.py", line 2218, in raise_construction_error
    raise ValueError(f"Shape of passed values is {passed}, indices imply {implied}")
ValueError: Shape of passed values is (2, 2), indices imply (4, 2)

Issue Description

Note that this bug does not exist on the latest version of pandas (v2.0.2). I think axis may have been messed up somewhere, will investigate.

Expected Behavior

>>> import pandas as pd
>>> df1 = pd.DataFrame({"a": range(2), "b": range(2)}, dtype="datetime64[s]")
>>> df2 = pd.DataFrame({"a": range(2), "b": range(2)}, dtype="datetime64[ns]")
>>> pd.concat([df1, df2])
                            a                           b
0         1970-01-01 00:00:00         1970-01-01 00:00:00
1         1970-01-01 00:00:01         1970-01-01 00:00:01
0         1970-01-01 00:00:00         1970-01-01 00:00:00
1  1970-01-01 00:00:00.001000  1970-01-01 00:00:00.001000

Installed Versions

INSTALLED VERSIONS
------------------
commit           : 4149f323882a55a2fe57415ccc190ea2aaba869b
python           : 3.9.6.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
Version          : 10.0.22621
machine          : AMD64
processor        : Intel64 Family 6 Model 158 Stepping 10, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : en_US.UTF-8
LOCALE           : Chinese (Simplified)_China.936

pandas           : 2.1.0.dev0+956.g4149f32388
numpy            : 1.24.3
pytz             : 2023.3
dateutil         : 2.8.2
setuptools       : 56.0.0
pip              : 23.1.2
Cython           : 0.29.33
pytest           : 7.3.1
hypothesis       : 6.75.9
sphinx           : 6.2.1
blosc            : 1.11.1
feather          : None
xlsxwriter       : 3.1.2
lxml.etree       : 4.9.2
html5lib         : 1.1
pymysql          : 1.0.3
psycopg2         : 2.9.6
jinja2           : 3.1.2
IPython          : 8.14.0
pandas_datareader: None
bs4              : 4.12.2
bottleneck       : 1.3.7
brotli           :
fastparquet      : 2023.4.0
fsspec           : 2023.5.0
gcsfs            : 2023.5.0
matplotlib       : 3.7.1
numba            : 0.57.0
numexpr          : 2.8.4
odfpy            : None
openpyxl         : 3.1.2
pandas_gbq       : None
pyarrow          : 12.0.0
pyreadstat       : 1.2.2
pyxlsb           : 1.0.10
s3fs             : 2023.5.0
scipy            : 1.10.1
snappy           :
sqlalchemy       : 2.0.15
tables           : 3.8.0
tabulate         : 0.9.0
xarray           : 2023.5.0
xlrd             : 2.0.1
zstandard        : 0.21.0
tzdata           : 2023.3
qtpy             : None
pyqt5            : None

[Charlie-XIAO]

take