E127: method chaining

I use method chaining in pandas very often, for example

import pandas as pd
df = (pd.read_csv('very/long/path/to/file/abcdefghijklmnopqrstuvwxyz.csv',
                  index_col='bar', encoding='utf-8')
        .drop(labels='baz', axis=1))

in which I indent the lines according to the first dot . after pd.

Now sometimes, this works:

but also sometimes it doesn't, for example when the first part exceeds into a new line:

Any idea what's going wrong here?

I am using Spyder 4.0.0 | Python 3.7.3 64-bit | Windows 10

Reproduce the two method-chaining examples with pycodestyle and compare the E127 results, using the repository's single Python implementation as the entry point. Trace how indentation is determined when the first chained expression wraps, then add coverage and make the reported behavior consistent for both examples.