Error while using webdatagrid to bind my columns

Hello guys,
I am using webdatagrid to bind my columns, but when doing so, I am met with an error. This error occurs when I try to update the third row of the same cell. I have no problems when clicking the first and second rows. They work well, but on clicking the third row, I get an error:
'Async request failed [MissingRecordException]: Requested record cannot be found by key'
The screenshot of the error is attached below:

Please guide me how to remove this error. I'll be really thankful for your suggestions.
Looking forward to hear from you soon.
Kindest regards.
