Have a problem in Numbers with entering data directly into a cell when a table reaches a certain size and special characters are used?

I am creating a list of words with special characters in some of them. I get to a point where I cannot enter data directly into the cell. I have to use the data entry bar at the top in the toolbar. Any solutions available?

This is the table I am creating...

From row 25 on, I am only able to enter data into the cell through the toolbar at the top and not directly into the cell itself. I believe that this problem originates from the special characters I have inserted in the previous records because if I do not use special characters, then the spreadsheet acts flawlessly. Have there been issues in Numbers with data entry, the size of a table, and using special characters?