Numbers double layers?

there's a good chance you duplicated your original table so now there is a copy on top of the original.

Active table:

to remove one of them, activate one by selecting any cell. Then drag the table using the move control(the blue concentric circles at the top left):

Now select the table on the right by clicking outside the table (the square on the top-right of the line) and drag to the inside of the table, then release. now type the delete key