Problem with visibleIf and expession

Hello.
I found an issue with expression and visibleIf condition.

Example:
We have 2 number inputs and expression field which sums these two inputs, and 2nd input is visible only if 1st input is > 0.

User starts filling 1st input - 2nd input becomes visible.
User is filling 2nd input.
Then user sets "0" value to the 1st input - 2nd input becomes invisible.
Expression field shows the sum with hidden 2nd input.

Here is JSON:

Code
{
 pages: [
  {
   name: "page1",
   elements: [
    {
     type: "text",
     name: "question1",
     inputType: "number"
    },
    {
     type: "text",
     name: "question2",
     visibleIf: "{question1} > 0",
     inputType: "number"
    },
    {
     type: "expression",
     name: "question3",
     expression: "{question1} + {question2}"
    }
   ]
  }
 ]
}

I made a video for better understanding: https://monosnap.com/file/P0brAMv99RfGdlHAax2aVVKVtyFNie

Is it possible to set a value to default or null when field becomes invisible?