NULL value for previous value is not being recognized

I am trying to reverse a bunch of records that I had erroneously go through a campaign with the incorrect logic (ANY vs AND... ugh).  In any event, I need to start with the low hanging fruit and change a bunch of records that went from NULL to a specific value.  I see in the log for my smart campaign, that there were numerous instances of this and yet, when I try to put in the following logic:

Data Value Changed

• Attribute ___Attribute1
• Previous Value____NULL
• New Value____Value 1
• Date of Activity between 12/18/2020 and 12/19/2020

I continue to get no qualified results, but if I try a specific value to and from, I get qualified results. 

I went so far as to also try null, [null] and blank doesn't work, as we all know, so I am stuck.  Any ideas?