Date value in IF note

Hello, I am trying to filter out json that happen before last month and it seems like my IF node is not working well.

It seems like the date format are the same, but there is an error say that it is not a valid DateTime format.

One of the expressions in Value 1 and Value 2 is likely resolving to undefined while iterating over the inputs. What is the input you are working with? I can tell that one of the values is pointing to an expression from a node that returns a single value. To fix the issue, you have to use $item(0) in the expression that is referencing only one item.