Sort list items with conditional logic issue

Hi,

I would like to sort my list items with help of "Sort list items" option together with conditional logic. In conditional logic I would like to check for appstate variable and based on its value sort dfferently.

However I ended up in "Current variable is not valid".

If I just choose "item in List" -> Get Document Property -> Cheapest price, sorting works.

I very appreciate your help. Thanks.