jQuery Grid Plugin - jqGrid

I have an issue with the jqgrid.

I use the datainit to handle the grid.

But there is some issue,

I click on one of the cell to change the value and I also manually change the other cellvalue by

 $('#customFieldsGrid').jqGrid('setCell', rowId, 'DefaultValue', data.DefaultValue());

I also update my view model.

I load the grid my using 

var grid = $('#customFieldsGrid');

var rows = [];

model.CustomObjectItemsData().forEach(function (item) {

                var cell = [];

cell.push(....);

rows.push({ id: item.ID(), cell: cell });

});

grid[0].addJSONData({

page: model.PageNumber(),

records: model.TotalRows(),

total: model.TotalPages(),

rows: rows

)};

and data showup in the grid perfectly.

But when I start clicking some other cell, within the same column.

The data of the previous cell that I edit will be blanked out from the grid.