I have a table with a column set up as a data validation list. It seems to works fine sometimes, but when I add a new row sometimes, the data validation drop down list disappears and it is no longer set up as a data validation list. My line for the list is set up as shown below:

=OFFSET('Packages'' Shipping Details'!$C$2,0,0,COUNTA('Packages'' Shipping Details'!$C:$C)-1)

Perhaps there's a setup feature I'm missing in the data validation. Any thoughts or advice would be greatly appreciated.

Thank you!