un-narrowing to Unknown regression

[beauxq]

Describe the bug
If something has been narrowed to a specific type, an in check can remove the narrowing information - for example changing str to Unknown

Code or Screenshots

from typing import Any, reveal_type


def foo(a: object, d: dict) -> None:
    if not isinstance(a, str):
        return
    reveal_type(a)  # str
    if a not in d:
        return
    reveal_type(a)  # Unknown should be str


def goo(a: object, d: dict[Any, Any]) -> None:
    if not isinstance(a, str):
        return
    reveal_type(a)  # str
    if a not in d:
        return
    reveal_type(a)  # Any should be str

version

1.1.389
1.1.380
1.1.379 <- problem not present