One anecdote in the same vein, a couple of months ago, I wanted to parse systemd-networkd INI files in Python and the python built-in ConfigParser [0] and pytest's iniconfig parser [1] couldn't handle multiple sections with the same name so I ended up writing 2 parsers, one using a ParserCombinator library and one by hand and ended up using the latter given it was much simpler to understand and I didn't have to introduce an extra dependency.

Admittedly, INI is quite a simple format, hence I mention this as an anecdote.

[0] https://docs.python.org/3/library/configparser.html

[1] https://github.com/pytest-dev/iniconfig