Get Quote and Quote Items using Magento 2 SOAP API

I am working with Magento 2 Rest APIs ( For Abundant cart ) and having issue with Quotes, I am able to get all Quotes ( with desired filters, is_active = 1, items_count > 0 ) using API :

/rest/V1/carts/search

and its items

/rest/V1/carts/:quoteId/items

Now, issue is in certain quotes it doesn’t return any items though when i check quote_item table i could see items are there.

And when i check quote total using :

/rest/V1/carts/:quoteId/totals

it returns desired results.

Now I’m little confuse how Quotes working and i have below questions :

1 – Why Quote items returned via API are different then the items in Database.

2 – Why some Quotes return items using /rest/V1/carts/search and some quotes doesn’t ?

3 – Strange case i have found is , a quote has 4 items 3 items converted to order and 1 item is not converted. however when i see quote totals it gives value of all 4 items.