Object cannot be found when third row is selected in datagrid

I'm creating a keyword test to fill out a table with settings in a datagrid. I mapped the first cell in the next row to create a new line. This is working for the first two records. But when filling out the third line the test stops with the log: object cannot be found. But when I select the object and choose 'highlight on screen'  the correct object is shown.

For some reasen the object is not visible for the third record. I also tried to use a delay, but that is not the cause for this issue.

Any idea what could be the cause for this issue?