Description:
------------
Also see the test script. When yielding a generator which is based on an array, the first element is returned twice.

Test script:
---------------
// https://3v4l.org/gYB16

function createArrayGenerator() {
    yield from [
        1,
        2,
    ];
}

function createGeneratorFromArrayGenerator() {
    yield from createArrayGenerator();
}

foreach (createGeneratorFromArrayGenerator() as $value) {
    echo $value;
}

Expected result:
----------------
The entries 1 and 2

Actual result:
--------------
The first entry twice, then the second