Workflow for checking if item exist in another list

Question

I have created a workflow that checks if an item exist in another list (List B). The first thing it does is to add an unique ID to the item, if it is a new item. If I am updating an item, the workflow will use this ID to check if the item exists in another list. For this I have created a Variable (Project ID).

I have inserted a condition saying "If List B: Project ID equals Variable: Project ID" (Find the List item field is set to Field Project ID, Value: Variable: Project ID)

This should tricker an action: "Log [%Current Item:Project Number%] already exists in List B", but it doesn't work.

However if I replace the definisions with Title, it works. But if I replace it with Project nr it goes back to not working

(in both cases I haven't changed the Find the List item)

I have added a picture of my workflow below.

Answer 1

1- Instead of setting the variable ProjectID to the current Items ID field,
set the ProjectID variable to the projectID in the other list, using Find the list Item by setting the ProjectID on the other list with the ProjectID of the Current Item.

2- then check IF the variable is Empty, if not empty means the item is exists.

Answer 2

And now it doesn't work again. I have deleted the workflow and started over. It seems to be another field that is causing the problem.