Make sure to have new IDs for the plots in the new CSV!
The plot ID, the first column of the CSV, contains the unique ID of the plot, by whcih which it is identified in hte the database.
If in the new CSV file you used the same IDs as in the original (probably a sequence 1,2,3... ) then Collect Earth will think that the plots already are filled.
To avoid this issue lease please make sure that in the new CSV the IDs are different, i.e. you might add a prefix or start the sequence from 1000 or another number, to make usre sure that they don't match the old ones
Let us know if that fixes the issue