Margin Preferences Scripting Exception Or Bug?

Hi Everyone,

I am stuck here. I am confused whether it is a bug or I misunderstood.

When I am changing margin preferences of individual pages the code works. But when I am trying to change margin preferences of all pages at once then code doesn't work.

This code works:

for(var i = 0; i < app.documents[0].pages.length; i++){
    app.documents[0].pages[i].marginPreferences.left = 12;
    app.documents[0].pages[i].marginPreferences.right = 12;
    app.documents[0].pages[i].marginPreferences.top = 12;
    app.documents[0].pages[i].marginPreferences.bottom = 12;
    }

& This code doesn't work:

app.documents[0].pages.everyItem().marginPreferences.left = 12;
app.documents[0].pages.everyItem().marginPreferences.right = 12;
app.documents[0].pages.everyItem().marginPreferences.top = 12;
app.documents[0].pages.everyItem().marginPreferences.bottom = 12;

And there is one more point to mention:

I can access margin preference of document like :

app.documents[0].marginPreferences.left = 12;
app.documents[0].marginPreferences.right = 12;
app.documents[0].marginPreferences.top = 12;
app.documents[0].marginPreferences.bottom = 12;

But I am not able to access these :

app.documents[0].marginPreferences.columnCount = 2;
app.documents[0].marginPreferences.columnGutter = 25;

I need to understand whether this has to do with any specific version of InDesign or is there any limitation or any other reason.

Please guide me on this.

I am using Windows OS & InDesign CC 2019.

Thanks

Sunil