Vaddin Grid with already sort applied, doesn't show all the data until refr

Flow
1

As per my understanding,
If the grid is having more number of rows, say 4000, then the Vaadin grid divides it internally into smaller sets and loads only the one applicable to the view port and other sets adjacent to it.
This works fine without any sorting enabled.
But if there is already some sort applied on the table and I just update the data bound it to with a new set of 4000 rows, the viewport doesn’t always show the full data.
If I do some editing or sorting again on the table manyally, the view port gets updated with the actual data.

2

This issue doesn’t seem to be because of the Vaadin Grid, but the way I am fetching data from the data source in chunks and binding to the UI.
Please ignore this question for now.
Thanks