Hi there! It sounds like you might have some hidden or filtered out values in your column. Here's how you can fix it:

1. Select the column that you want to filter.
2. Go to the Data tab in the ribbon and click on Filter (or use the keyboard shortcut
   Code:

   Ctrl + Shift + L

   ).
3. Click on the drop-down arrow in the column header that you want to filter.
4. Check if there are any values that are unchecked. If there are, check them to include them in the filter.
5. If there are still missing values, click on Filter by Color and select No Fill to show any hidden values that might be present.
6. If none of the above steps work, it's possible that there are some formatting issues with your data. Try selecting the column and going to Home tab in the ribbon, then click on Clear and select Clear All to remove any formatting that might be causing the issue.

I hope this helps! Let me know if you have any other questions.