Improve cell link formula

Sespedido_23

While doing the cell link formulas, one of the columns shows data even if the key identifier used is blank (Client ID), would you know why is it happening? but when the client ID column is filled, the column/row were able to update/pull the correct data.

here's the formula I used:

=INDEX({Client View Sales Region}, MATCH([Client ID]@row, {Client View Client ID}, 0))

Leroy Noriega

The sheet the data is being extracted from could have a black Client ID and whatever that row contains is what is being pulled. I would look through the data for any missing Client ID or extra rows.