Ignore Blanks with Validation not working with Formula's

Hello all

I have a master sheet with a column using a simple Y/N data validation list. Then I have a project sheet, where the corresponding column has the same validation list. That column has a formula that pulls the values from the master sheet, and fails when the values are empty on the master sheet - even though I have "Ignore blanks" on both sheets. You might ask why do I have a validation rule on a formula. The reason is that the original value for that column comes from the master, but can be changed manually in the project sheet.

My assessment here is that the validation list is not really meant to validate formulas, but only data entry. So how do I solve this?

It is very easy to replicate the issue:

Create a blank screen
Add a data validation list on one field: =Y, N and set "Ignore Blanks" to true
Then in the same field add a formula =""

And you will get the error right away.

How do I solve this? I.e. have data validation list with Ignore blanks set to true, and then have a formula that returns blank?

Thanks

-Jan