BUG: unexpected cut() results
- [X] I have checked that this issue has not already been reported.

- [X] I have confirmed this bug exists on the latest version of pandas.

- [ ] (optional) I have confirmed this bug exists on the master branch of pandas.

---

**Note**: Please read [this guide](https://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports) detailing how to provide the necessary information for us to reproduce your bug.

#### Code Sample, a copy-pastable example

```python
import pandas as pd
nbins = 42
maxs = [96, 97, 98]

for max in maxs:
    data = [-max, 0, max]
    bins = pd.cut(data, nbins, labels=False)
    print("Data: ", data)
    print("Bins: ", bins, "\n")
```

#### Problem description

According to [documentation](https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.cut.html), I would expect the `0` value to go to the bin `20`. For `max == 96` and `max == 98` it does go to the bin `20`, however, when `max == 97` for some reason `0` goes to the bin `21`:

```python
Data:  [-96, 0, 96]
Bins:  [ 0 20 41]

Data:  [-97, 0, 97]
Bins:  [ 0 21 41]

Data:  [-98, 0, 98]
Bins:  [ 0 20 41]
```

Feels like a bug, or may be I'm missing something on the docs that explains such a `cut()` behavior. Would appreciate any help on this. Thanks.

#### Expected Output

```python
Data:  [-96, 0, 96]
Bins:  [ 0 20 41]

Data:  [-97, 0, 97]
Bins:  [ 0 20 41]

Data:  [-98, 0, 98]
Bins:  [ 0 20 41]
```

#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit           : None
python           : 3.6.8.final.0
python-bits      : 64
OS               : Darwin
OS-release       : 19.2.0
machine          : x86_64
processor        : i386
byteorder        : little
LC_ALL           : None
LANG             : en_US.UTF-8
LOCALE           : en_US.UTF-8

pandas           : 1.0.5
numpy            : 1.16.1
pytz             : 2018.9
dateutil         : 2.8.0
pip              : 20.0.2
setuptools       : 40.6.3
Cython           : None
pytest           : 4.1.1
hypothesis       : None
sphinx           : 2.4.4
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : None
html5lib         : None
pymysql          : None
psycopg2         : None
jinja2           : 2.10
IPython          : 7.8.0
pandas_datareader: None
bs4              : None
bottleneck       : None
fastparquet      : None
gcsfs            : None
lxml.etree       : None
matplotlib       : None
numexpr          : None
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pytables         : None
pytest           : 4.1.1
pyxlsb           : None
s3fs             : None
scipy            : None
sqlalchemy       : None
tables           : None
tabulate         : None
xarray           : None
xlrd             : 1.2.0
xlwt             : None
xlsxwriter       : None
numba            : None


</details>
