Row1 is null when adding new row

Here I have a little problem with my table...

When I'm trying to add a new row using this.resolveNode("Table.Row1").instanceManager.addInstance(1);

It pops me an error such as:

TypeError: this.resolveNode("Table.Row1") is null...

This error pops up once I have 2 rows... it can't add a third row....

If I write :

this.resolveNode("Table.Row1[0]").instanceManager.addInstance(1);

It will add a row no problem. BUT the problem is when I save the form and reopen the form... there's only the first row (Row1[0]) and it's data that is showing up on the form...

Anyone knows how can I fix this?