Lambda that uses INDEX with array arguments behaves inconsistently when saved in the Name Manager

I updated an enterprise M365 today to version 2607 (Build 20228.20110) and the issue is still present.  There's no sign of the problem on the Beta channel. The fix implemented there is apparently not ready for production yet. It'd be interesting to know more specifics.

I do most of my development work in v2606 and I've noticed it. From what I've tested in Beta/Insider channel, the quirk does not exist.

The common thread in testing seems to be this quirk exists for lookup/retrieval functions (e.g., INDEX, VLOOKUP, XLOOKUP, etc.) but does not surface for shaping/selection functions (TOCOL, CHOOSEROWS, SORT, FILTER, etc.). BTW - I would not include Excel for the web in Lambda tests because that version doesn't fully support Lambda (e.g. Element-to-Apply (ETA) evaluation) and doesn't always resolve AFE modules well.

// These results require coercion
TestAλ=
LAMBDA(
    array,
LET(
    arbit,INDEX(array,SEQUENCE(4),1),
    arbit
));

TestBλ=
LAMBDA(
    array,
LET(
    arbit,VLOOKUP(TAKE(array,,1),array,2,0),
    arbit
));

TestCλ=
LAMBDA(
    array,
LET(
    arbit,XLOOKUP(TAKE(array,,1),TAKE(array,,1),TAKE(array,,-1)),
    arbit
));

// These results do not require coercion
TestDλ=
LAMBDA(
    array,
    FILTER(array,SEQUENCE(ROWS(array)))
);


TestEλ=
LAMBDA(
    array,
    CHOOSEROWS(array,SEQUENCE(ROWS(array)))
);


TestFλ=
LAMBDA(
    array,
    SORT(array)
);


TestGλ=
LAMBDA(
    array,
    TAKE(array,3)
);


TestHλ=
LAMBDA(
    array,
    TOCOL(array)
);

TestIλ=
LAMBDA(
    array,
    CHOOSECOLS(array,SEQUENCE(COLUMNS(array)))
);

TestJλ=
LAMBDA(
    array,
    WRAPROWS(TOCOL(array),COLUMNS(array))
);

not sure why this is happening but I was able to confirm and get this image of the desktop application on the left and the online version on the right of the exact same file showing the difference in results:

a couple other things of interest include the Excel Labs tool showing in both cases the correct answer and even identifying on the web version that it's answer doesn't match the result shown on the grid.  

Also hovering on the indx function (which is the lambda function) on the web version is showing a #CALC! error.  Although I would point to this as a place to start I will also note that if I highlight the indx function on the desktop it shows a result of 1 instead of the expected {1,2,4} so that isn't correct on the desktop either.

as a workaround I was able to break INDEX into a combination of CHOOSECOLS(CHOOSEROWS()) and that worked:

=LAMBDA(arr,CHOOSECOLS(CHOOSEROWS(arr,{1}),{1,2,4}))

Interesting the hover over on the web version still says #CALC! but now hover over on the app does correctly say {1,2,4}