Conditional Formatting Using Names Ranges - No Errors?

Hi guys, long time no see.

I'm being driven mad by a problem I'm having - I've set up data validation for some cells using named ranges on another sheet.

The drop-down works and shows the correct options, but when I overtype anything else, and would normally expect an error message to show, nothing happens. I've tried using a direct reference on the same sheet and the error message works fine, so it definitely seems to be related to using named ranges.

Is this a known issue? I can't seem to find anything about it. Any help would be MASSIVELY appreciated.

EDIT - I seem to have fixed this by de-selecting the 'Ignore Blank' option in the Data Validation settings screen. Also, sorry for any confusion with the title, this has nothing to do with Conditional Formatting - may also explain why I struggled to find anything about it when searching... Can the title be changed to Data Validation somehow? Just thinking for anyone else searching, not really much use to them.

And if anyone would care to explain what this 'Ignore Blanks' does, that would be great!