Generator function behaves differently in various iteration contexts

Question

So I have this generator function for non-recursive permutations, when I use it in for loop, I get what I expect:

>>> for p in permutate3( "abc" ): print( p )
...
['a', 'b', 'c']
['a', 'c', 'b']
['b', 'a', 'c']
['b', 'c', 'a']
['c', 'a', 'b']
['c', 'b', 'a']

But once I use it in list or print with argument unpacking I get this strange output:

>>> list( permutate3( "abc" ) )
[['c', 'b', 'a'], ['c', 'b', 'a'], ['c', 'b', 'a'], ['c', 'b', 'a'], ['c', 'b', 'a'], ['c', 'b', 'a']]
>>> print( *permutate3( "abc" ) )
['c', 'b', 'a'] ['c', 'b', 'a'] ['c', 'b', 'a'] ['c', 'b', 'a'] ['c', 'b', 'a'] ['c', 'b', 'a']

Why does this happen?..

The function itself is:

def permutate3( s ):
    l = len( s )
    taken = [ False ] * l
    permutation = [ None ] * l
    current = 0
    stack = [ 0 ]

    while True:
        while stack[-1] < l:
            if not taken[ stack[-1] ]:
                permutation[current] = s[ stack[-1] ]
                if current == l-1:
                    yield permutation
                else:
                    taken[ stack[-1] ] = True
                    stack.append( 0 )
                    current+=1
                    break
            stack[-1]+=1
        else:
            stack.pop()
            if len( stack ) == 0:
                break
            else:
                current-=1
                taken[ stack[-1] ] = False
                stack[-1]+=1
                continue

Answer 1

Dummy me. My function yields reference to the same object every time, which is changed by the function for subsequent permutations. Obviously it should be yield list( permutation ).