composing generator expression doesn't work as expected

[TsvikaShapira]

BPO	36627
Superseder	bpo-7423: nested generator expression produces strange results

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2019-04-14.10:15:16.891>
created_at = <Date 2019-04-14.09:32:03.322>
labels = ['invalid', 'type-bug', '3.7']
title = "composing generator expression doesn't work as expected"
updated_at = <Date 2019-04-14.10:15:16.886>
user = 'https://bugs.python.org/TsvikaShapira'

bugs.python.org fields:

activity = <Date 2019-04-14.10:15:16.886>
actor = 'SilentGhost'
assignee = 'none'
closed = True
closed_date = <Date 2019-04-14.10:15:16.891>
closer = 'SilentGhost'
components = []
creation = <Date 2019-04-14.09:32:03.322>
creator = 'Tsvika Shapira'
dependencies = []
files = []
hgrepos = []
issue_num = 36627
keywords = []
message_count = 2.0
messages = ['340200', '340203']
nosy_count = 2.0
nosy_names = ['SilentGhost', 'Tsvika Shapira']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = '7423'
type = 'behavior'
url = 'https://bugs.python.org/issue36627'
versions = ['Python 3.6', 'Python 3.7']

[TsvikaShapira]

the following code:

lists_to_filter = [
    ['a', 'exclude'],
    ['b']
]
# notice that when 'exclude' is the last element, the code returns the expected result
for exclude_label in ['exclude', 'something']:
    lists_to_filter = (labels_list for labels_list in lists_to_filter if exclude_label not in labels_list)
    # notice that changing the line above to the commented line below (i.e. expanding the generator to a list) will make the code output the expected result, 
    # i.e. the issue is only when using filter on another filter, and not on a list
    # lists_to_filter = [labels_list for labels_list in lists_to_filter if exclude_label not in labels_list]
lists_to_filter = list(lists_to_filter)
print(lists_to_filter)

as far as i understand, the code above should output "[['b']]"
instead it outputs "[['a', 'exclude'], ['b']]"

[SilentGhost]

I probably won't be able to better explain the issue then Benjamin did in the referenced issue. Just to note, that (...) in your code are called generator expressions.