Admittedly what I'm about to say is a border case and not reporting a bug: I can't help but see a way to have passing functions break, after the following procedure:

subclass the list class, break it somehow; put an instance of that object in your dataframe and suddenly the function no longer works.
For example:

class TrickyList(list):
    def __iter__(self): 
        pass
        
tl = TrickyList()
print(isinstance(tl, list)) # True
tricky_df = pd.DataFrame(data=[[tl,5], [77, 3]], 
                        columns=list('AB'))
flatten(tricky_df, 'A') # TypeError: iter() returned non-iterator of type 'NoneType'

OK, that was just me having fun with an edge case...

not a kata issue

Let's say we have the following configuration: 100 bullions and 5 pirates. Then we have the following optimal configuration: [98, 0, 1, 0, 1], as it was noted here.

According to that logic, I think for 30 bullions the right answer is [28, 0, 1, 0, 1], but not the [27, 0, 1, 0, 2]. What am I missing?

yeah that's embarassing
corrected thks

[0,3,1,1,0]

What happens to the other 25 bullions?

done thanks

done

given that all pirates want as big a share of the treasure as possible, there is a forced equilibrium.
will make it clearer, thanks for the feedback

I think they are to most people indeed, I just have a few weeks only of Python (and any form of code actually
) behind me and know decorators for a few hours...

There is an optimal split for this problem assuming all pirates are intelligent and rational, find it!

What is the criteria of optimality here?

It doesn't seem there is any good reason for using different font sizes and styles, they are merely distracting.

You can divide the description into sections, if you want.

Is this part really not that clear? Or this example? Or this example?

I am honestly asking, I thought they are rather clear, but if they are not, they need some improvements.

You should have more than one test!
You need several static tests covering edge cases and enough random tests to avoid hardcoding.
See these:
https://docs.codewars.com/languages/python/authoring/

You should unpublish before it gets retired 😬

Then come to the gitter channel mentioned by @XRFXLP, it should be much easier to explain there.