Problem with Date: "" is not a valid date

Good afternoon,
Could someone please help me solve this problem:
Why do I get this conversion errors: Date: "" is not a valid date.

I have a task that needs to delete the date if it is # in a row
I achieved this using the multi-field formula:

IF [Head of State] = "#" THEN "" ELSE [_CurrentField_] ENDIF

However, it gives me this error. Could someone please help me to get it right.

Workflow

Accepted answers

Change formula like below. Replace quotes with Null() it will give you the same output.

IF [Head of State] = "#" THEN Null() ELSE [_CurrentField_] ENDIF

Hope this helps : )

Change formula like below. Replace quotes with Null() it will give you the same output.

IF [Head of State] = "#" THEN Null() ELSE [_CurrentField_] ENDIF

Hope this helps : )

Yes it works, thank you very much for your help!:)